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logarithm/529650: how does 8x^3=e^18 equal 2x=e^6
1 solutions

Answer 349648 by josmiceli(9817) About Me  on 2011-11-10 14:38:51 (Show Source):
You can put this solution on YOUR website!
+8x%5E3=e%5E18+
+%282x%29%5E3+=+e%5E18+
Take the cube root of both sides
+2x+=+e%5E6+
Note that
+e%5E6%2Ae%5E6%2Ae%5E6+=+e%5E%28+6+%2B+6+%2B+6+%29+
+e%5E%28+6+%2B+6+%2B+6+%29+=+e%5E18+


Expressions-with-variables/529648: My question is whats substition I keep hearing about? How does it work? Can you tell me how to solve a problem using substition?
1 solutions

Answer 349645 by josmiceli(9817) About Me  on 2011-11-10 14:31:32 (Show Source):
You can put this solution on YOUR website!
Sure.
Suppose you have 2 equations with
2 unknowns. It definitely should be
solvable, and one way is by substitution.
Say the equations are
(1) +x+-+y+=+10+
(2) +3x%5E2+%2B+9y%5E2+=+300+
-----------------------
From(1), I get
(1) +x+=+y+%2B+10+
Now I will Substitute this value of x
into equation (2)
(2) +3%2A%28+y+%2B+10+%29%5E2+%2B+9y%5E2+=+300+
(2) +3%2A%28+y%5E2+%2B+20y+%2B+100%29+%2B+9y%5E2+=+300+
(2) +3y%5E2+%2B+60y+%2B+300+%2B+9y%5E2+=+300+
(2) +12y%5E2+%2B+60y+=+0+
(2) +12y%2A%28y+%2B+5%29+=+0+
+y+=+0+
+y+=+-5+
The solutions are
(10,0) and (5,-5)


Rational-functions/529620: Please help!
I have to solve by factoring. Not sure how to get the answer to these:
x^3 -10x + 25x = 0
and
2x^3 -8x = 0
Thanks for the help
1 solutions

Answer 349644 by josmiceli(9817) About Me  on 2011-11-10 14:14:34 (Show Source):
You can put this solution on YOUR website!
+x%5E3+-10x%5E2+%2B+25x+=+0++
+x%2A%28x%5E2+-+10x+%2B+25%29+=+0+
Either of these 2 factors must be 0, so
+x+=+0+ is a solution and
+x%5E2+-+10x+%2B+25+=+0+
This is a perfect square
+%28+x+%2B+5+%29%5E2+=+0+
+x+=+-5+ is also a solution
---------------------
+2x%5E3+-+8x+=+0+
+2x%2A%28+x%5E2+-+8+%29+=+0+
+x+=+0+ is a solution
also
+x%5E2+-+8+=+0+
+x+=+sqrt%288%29+
+x+=+2%2Asqrt%282%29+ and
+x+=+-2%2Asqrt%282%29+
are both solutions


Probability-and-statistics/529602: If two cards are drawn from a standard 52 card deck without replacement, in how many different ways is it possible to obtain a heart on the first draw and an ace on the second?
1 solutions

Answer 349640 by josmiceli(9817) About Me  on 2011-11-10 13:33:12 (Show Source):
You can put this solution on YOUR website!
I'd get a 2nd opinion on this, but here's my view:
There are 13 ways that you can draw a heart first
Having drawn the heart, there are 4 ways to draw
an ace, so there are +13%2A4+=+52+ ways to get
this combination. But what if the 1st card is the
Ace of hearts. Then there are only 3 ways to draw
an Ace. So I have to subtract the one combination
that I counted twice, that is Ace of hearts and
Ace of hearts again.
There are then 51 ways to draw a heart and then
an Ace. Hope I got it.


percentage/529617: how to do percentages.
1 solutions

Answer 349635 by josmiceli(9817) About Me  on 2011-11-10 13:17:16 (Show Source):
You can put this solution on YOUR website!
You need to fix in your mind that
per cent means "per one-hundred"
Think of the % sign as saying: you need to
divide this number by 100.
-------------------------
Suppose I say 67%
% means to divide it by 100, so
what I really have is 67/100 = .67
------------------------
Another problem you will see is:
convert .67 to a percent
The algebra for this is
.67 = x/100
This says: .67 is what percent ?
Multiply both sides by 100
67 = x, so
67/100 = 67 percent
Hope this helps


percentage/529379: If my portfolio grows by 10% then i now havw 150$.How much did I originally have?
1 solutions

Answer 349585 by josmiceli(9817) About Me  on 2011-11-09 23:29:38 (Show Source):
You can put this solution on YOUR website!
You originally has +x+ dollars
given:
+x++%2B+.1x+=+150+
+1.1x+=+150+
+x+=+150+%2F+1.1+
+x+=+136.36+
You originally had $136.36


Exponential-and-logarithmic-functions/529392: 4log5(x+3)-log5(x-18)-log5(x-1)
1 solutions

Answer 349584 by josmiceli(9817) About Me  on 2011-11-09 23:21:50 (Show Source):
You can put this solution on YOUR website!
+4%2Alog%28+5%2A%28x%2B3%29+%29-+log%28+5%2A%28x-18%29%29+-+log%28+5%2C%28x-1%29%29+
+log%28+5%2C%28x%2B3%29%5E4+%29-+log%28+5%2C%28x-18%29%29+-+log%28+5%2C%28x-1%29%29+
+log%28+5%2C+%28+%28+x+%2B+3+%29%5E4+%2F+%28%28x-18%29%2A%28x-1%29%29%29+%29+
I'm not sure if it can be simplified beyond this


Numbers_Word_Problems/529346: find 3 consecutive odd integers such that the sum of four times the smallest integer and three times the largest integer is 159.
1 solutions

Answer 349564 by josmiceli(9817) About Me  on 2011-11-09 21:50:15 (Show Source):
You can put this solution on YOUR website!
Let the consecutive odd integers be
+n+, +n+%2B+2+, and +n+%2B+4+
given:
+4n+%2B+3%2A%28n+%2B+4%29+=+159+
+4n+%2B+3n+%2B+12+=+159+
+7n+=+147+
+n+=+21+
+n+%2B+2+=+23+
+n+%2B+4+=+25+
The numbers are 21, 23, and 25


Age_Word_Problems/529334: Mrs Sabado is 6 times as old as her daughter May. Next year her age will be equal to the square of her daughter's age. Find the present age.
1 solutions

Answer 349558 by josmiceli(9817) About Me  on 2011-11-09 21:41:22 (Show Source):
You can put this solution on YOUR website!
Let +a+ = Mrs. Sabado's age now
Let +b+ = May's age now
given:
(1) +a+=+6b+
(2) +a+%2B+1+=+%28+b+%2B+1%29%5E2+
----------------------
(2) +a+%2B+1+=+b%5E2+%2B+2b+%2B+1+
Substitute (1) into (2)
(2) +6b+%2B+1+=+b%5E2+%2B+2b+%2B+1+
(2) +b%5E2+-+4b+=+0+
(2) +b%2A%28+b+-+4+%29+=+0+
Either +b+=+0+ or +b+=+4+
If b+=+4,
(1) +a+=+6b+
(1) +a+=+24+
------------
If +b=0+, then
(1) +a+=+6b+
(1) +a+=+0+
This says they are both newborns, which
is impossible, so
24 is Mrs. Sabado's age now
4 is May's age now
check:
(2) +a+%2B+1+=+%28+b+%2B+1%29%5E2+
(2) +24+%2B+1+=+%28+4+%2B+1%29%5E2+
(2) +25+=+5%5E2+
(2) +25+=+25+
OK


Distributive-associative-commutative-properties/529323: what is the distributive property of algebra
1 solutions

Answer 349548 by josmiceli(9817) About Me  on 2011-11-09 21:18:17 (Show Source):


Inequalities/529309: Need assistance with this, i cant figure it out. It's driving me mad. Thank you.
Lena is choosing between two exercise routines.
In routine #1, she burns 25 calories walking. She then runs at a rate that burns 18 calories per minute.
In routine #2, she burns 49 calories walking. She then runs at a rate that burns 14 calories per 
minute.
For what amount of time spent running will routine #1 burn fewer calories than routine#2? Use t for the number of minutes spent running, and solve your inequality for t.
1 solutions

Answer 349543 by josmiceli(9817) About Me  on 2011-11-09 21:14:36 (Show Source):
You can put this solution on YOUR website!
Let t = minutes spent running
given:
Routine #1
Calories burnt = +25+%2B+18t+
Routine #2
Calories burnt = +49+%2B+14t+
------------------------
Let calories burnt = C
The question is:
for what values of t is
+49+%2B+14t+%3E+25+%2B+18t+
Subtract +14t+ from both sides
+49+%3E+25+%2B+4t+
Subtract +25 from both sides
+24+%3E+4t+
+6+%3E+t+
or, what is the same,
+t+%3C+6+
So, for all values of t+%3C+6+ minutes spent running,
The calories burnt using routine #1 are less than
the calories burnt using #2
Here's a plot of routine #1 and #2:
+graph%28+400%2C+400%2C+-1%2C+7%2C+-5%2C+150%2C+18x+%2B+25%2C+14x+%2B+49+%29+
The bottom line is routine #1. You can see that when +t+=+0+
+C+=+25+ as it should, and they meet at t=6


Money_Word_Problems/529293: Cliff had a total of $100,000 to invest. He put some of the money in Bank A that paid 4% interest and the rest in Bank B which paid 5% interest. After a year, the amount of interest he earned was $4850. How much money did Cliff invest in Bank A? Also provide a step by step procedure on how to get the answer.
1 solutions

Answer 349538 by josmiceli(9817) About Me  on 2011-11-09 20:51:27 (Show Source):
You can put this solution on YOUR website!
Let a = amount invested @ 4%
Let b = amount invested @ 5%
given:
(1) +a+%2B+b+=+100000+
(2) +.04a+%2B+.05b+=+4850+
--------------------
(2) +4a+%2B+5b+=+485000+
Multiply both sides of (1) by 4
and subtract (1) from (2)
(2) +4a+%2B+5b+=+485000+
(1) +-4a+-+4b+=+-400000+
+b+=+85000+
and, since
(1) +a+%2B+b+=+100000+
(1) +a+%2B+85000+=+100000+
(1) +a+=+15000+
Cliff invested $15,000 in bank A
check answer:
(2) +.04a+%2B+.05b+=+4850+
(2) +.04%2A15000+%2B+.05%2A85000+=+4850+
(2) +600+%2B+4250+=4850+
(2) +4850+=+4850+
OK


logarithm/529226: how do I evaluate this: log2 120 − log2 12 − log2 40
1 solutions

Answer 349527 by josmiceli(9817) About Me  on 2011-11-09 19:48:06 (Show Source):
You can put this solution on YOUR website!
+log%282%2C120%29+-+log%282%2C12%29+-+log%282%2C40%29+
+log%282%2C+120%2F%2812%2A40%29%29+
+log%282%2C+120%2F480%29+
+log%282%2C+1%2F4%29+
If I set this expression equal to x,
then +2%5Ex+=+1%2F4+
+2%5E%28-2%29+=+1%2F4+
The answer is:
+log%282%2C120%29+-+log%282%2C12%29+-+log%282%2C40%29+=+-2+


Money_Word_Problems/529205: John invested $8000 for one year, part at 8% interest and the rest at 10%. If John earned $700 in interest, how much is in each account?
1 solutions

Answer 349524 by josmiceli(9817) About Me  on 2011-11-09 19:31:33 (Show Source):
You can put this solution on YOUR website!
Let +a+ = amount invested @ 8%
Let +b+ = amount invested @ 10%
given:
(1) +a+%2B+b+=+8000+
(2) +.08a+%2B+.1b+=+700+
-----------------
(2) +8a+%2B+10b+=+70000+
(2) +4a+%2B+5b+=+35000+
Multiply both sides of (1) by 4
and subtract (1) from (2)
(2) +4a+%2B+5b+=+35000+
(1) +-4a+-+4b+=+-32000+
+b+=+3000+
and, since
(1) +a+%2B+b+=+8000+
(1) +a+=+8000+-+3000+
(1) +a+=+5000+
$5,000 is the amount invested @ 8%
$3,000 is the amount invested @ 10%
check answer:
(2) +.08a+%2B+.1b+=+700+
(2) +.08%2A5000+%2B+.1%2A3000+=+700+
(2) +400+%2B+300+=+700+
(2) +700+=+700+
OK


Expressions-with-variables/529203: can you please explain how to solve this problem.I'm trying to help my 5th grader understand. thanks=)
8+n if n=12,and 7xn if n=8
1 solutions

Answer 349517 by josmiceli(9817) About Me  on 2011-11-09 19:13:34 (Show Source):
You can put this solution on YOUR website!
+8+%2B+n+
given:
+n+=+12+
Replace n with 12
+8+%2B+12+=+20+
--------------
+7%2An+
given:
+n+=+8+
Replace n with 8
+7%2A8+=+56+
--------------


Angles/529201: the angels of an acute triangle are 2x, x, and x+10 what are the measurement of each angel
1 solutions

Answer 349514 by josmiceli(9817) About Me  on 2011-11-09 19:09:00 (Show Source):
You can put this solution on YOUR website!
The sum of the angles of a triangle are 180 degrees
+2x+%2B+x+%2B+x+%2B+10+=+180+
+4x+=+180+-+10+
+4x+=+170+
+x+=+42.5+
+2x+=+85+
+x+%2B+10+=+52.5+
The angles are 42.5, 52.5, and 85 degrees


Miscellaneous_Word_Problems/528674: One morning martin drove 80 miles in 2 hours. After lunch he covered 100 miles more in 3 hours. What was his average rate of speed in miles per hour for the 5 hours of driving?
1 solutions

Answer 349389 by josmiceli(9817) About Me  on 2011-11-09 03:34:09 (Show Source):
You can put this solution on YOUR website!
Average speed is always
( total distance ) / ( total time )
+%28+80+%2B+100+%29+%2F+%282+%2B+3%29+=+180%2F5+
+180%2F5+=+36+
The average speed is 36 mi/hr


Rate-of-work-word-problems/528667: One computer takes 21 minutes longer than a second computer to do the job. Working together these computers can do the same job in 10 minutes. How long would it take each computer working alone to do the same job?
1 solutions

Answer 349388 by josmiceli(9817) About Me  on 2011-11-09 03:31:07 (Show Source):
You can put this solution on YOUR website!
Add their rate of doing jobs to get
their rate together.
Let t = the time in minutes for the 2nd computer
to finish the job.
Then +t+%2B+21+ is the time for the 1st computer
to do the job
+1%2F%28+t+%2B+21%29+ is the 1st computer's rate
+1%2Ft+ is the 2nd computer's rate
+1%2F10+ is their rate working together
+1%2F%28t+%2B+21%29+%2B+1%2Ft+=+1%2F10+
Multiply both sides by +t%2A%28t+%2B+21%29%2A10+
+10t+%2B+10%2A%28t+%2B+21%29+=+t%2A%28t+%2B+21%29+
+10t+%2B+10t+%2B+210+=+t%5E2+%2B+21t+
+t%5E2+%2B+t+=+210+
Complete the square
+t%5E2+%2B+t+%2B+%281%2F2%29%5E2+=+210+%2B+%28t%2F2%29%5E2+
+%28+t+%2B+1%2F2+%29%5E2+=+840%2F4+%2B+1%2F4+
+%28+t+%2B+1%2F2%29%5E2+=+841%2F4+
+%28+t+%2B+1%2F2%29%5E2+=+%2829%2F2%29%5E2+
+t+%2B+1%2F2+=+29%2F2+
+t+=+28%2F2+
+t+=+14+ ( ignore the negative square root )
+t+%2B+21+=+35+
It will take the 1st computer 35 min
It will take the 2nd computer 14 min
check:
+1%2F%28t+%2B+21%29+%2B+1%2Ft+=+1%2F10+
+1%2F35+%2B+1%2F14+=+1%2F10+
Multiply both sides by +14%2A35+
+14+%2B+35+=+490%2F10+
+49+=+49+
OK


Numbers_Word_Problems/528694: One number is ten more than other. If the sum of twice the smaller number and three times the larger number is 55, find the two numbers.
1 solutions

Answer 349387 by josmiceli(9817) About Me  on 2011-11-09 03:06:07 (Show Source):
You can put this solution on YOUR website!
You can call the numbers x and +x%2B10+
given:
+2x+%2B+3%2A%28+x+%2B+10+%29+=+55+
+2x+%2B+3x+%2B+30+=+55+
+5x+=+55+-+30+
+5x+=+25+
+x+=+5+
+x+%2B+10+=+15+
check:
+2%2A5+%2B+3%2A%28+5+%2B+10+%29+=+55+
+10+%2B+45+=+55+
+55+=+55+
OK


Polynomials-and-rational-expressions/528696: This question is driving me up the wall. It has to be answered only in fractions and not in decimals.
Two thirds of two is what part of three
or put another way, 2/3 of 2 is x (what) part of 3.
I'm not sure, but the answer is 4/9, but how is the problem solved (step by step) to arrive at the figure of say 4/9 or whatever?.
I'm 80+ and still doing ok, no Alzheimer yet..ha-ha, many thanks for any help.
1 solutions

Answer 349386 by josmiceli(9817) About Me  on 2011-11-09 03:00:39 (Show Source):
You can put this solution on YOUR website!
1st I'll find
+%282%2F3%29%2A2+=+4%2F3+
What part of 3 is this?
+%284%2F3%29+%2F+3+=+4%2F9+
The way the problem is stated is just
a little different from usual, and
can throw you off.


Evaluation_Word_Problems/528695: A twelve foot board is cut into two pieces. One piece is two feet longer than the other piece. How long is each piece.
1 solutions

Answer 349385 by josmiceli(9817) About Me  on 2011-11-09 02:31:02 (Show Source):
You can put this solution on YOUR website!
Let the pieces be x and x%2B2 ft in length
given:
+x+%2B+x+%2B+2+=+12+
+2x+=+12+-+2+
+2x+=+10+
+x+=+5+
+x+%2B+2+=+7+
The pieces are 5 ft and 7 ft long


Permutations/528682: I am having a really hard time trying to figure out this question please help,all I know so far is that I should use permutation, but I don't know how:
Question:
A class consists of 60 ladies and 40 men. In how many ways can a president, vice president, treasurer and secretary be chosen if the treasurer must be a lady, the secretary must be a man and the student may not hold more than one office?
Thank you
1 solutions

Answer 349384 by josmiceli(9817) About Me  on 2011-11-09 02:27:51 (Show Source):
You can put this solution on YOUR website!
I'll take shot at it, but you might want to get
a 2nd opinion
Since the treasurer must be a lady, there are
60 different ways that office can be filled
Since the Secretary must be a man, there are
40 ways that office can be filled.
There are +60%2A40+=+2400+ different ways
that the 2 offices can be held
-------------------------
Once the Treasurer and Secretary offices have
been filled, there are +59+%2B+39+=+98+
people left to fill President and Vice-President
There are +98%2A97+ different ways to fill
these 2 offices ( M or F doesn't matter )
-------------------------
The 4 offices can then be filled in
+60%2A40%2A98%2A97+ different ways.
( I lost calculator, you can finish )


Equations/528541: In a fifth-grade class of 16 students, one-half of the students showed up early, one-fourth of the students showed up on time and one-eighth showed up late. How many students were absent?
1 solutions

Answer 349322 by josmiceli(9817) About Me  on 2011-11-08 20:25:00 (Show Source):
You can put this solution on YOUR website!
+1%2F2+%2B+1%2F4+%2B+1%2F8+=+4%2F8+%2B+2%2F8+%2B+1%2F8+
+7%2F8+
+1+-+7%2F8+=+1%2F8+
1/8 of the students were absent
+%2812%2F8%29%2A16+=+2+
2 students were absent


Evaluation_Word_Problems/528539: The class average on a test is exactly 83. take away the best score and the average is 82. There are 16 students in the class, what is the best score?
x/16=83-x/16???
1 solutions

Answer 349319 by josmiceli(9817) About Me  on 2011-11-08 20:20:17 (Show Source):
You can put this solution on YOUR website!
Let s = sum of scores of all 16 students in class
Let h = the highest score of the 16 students
With all the students in class:
(1) +83+=+s+%2F+16+
With highest score taken away:
(2) +82+=+%28+s+-+h+%29+%2F+15+
------------------
This is 2 equations and 2 unknowns, so it's solvable
(1) +s+=+16%2A83+
(2) +15%2A82+=+s+-+h+
Substitute (1) into (2)
(2) +15%2A82+=+16%2A83+-+h+
(2) +h+=+16%2A83+-+15%2A82+
Can't find my calculator- you can finish


Travel_Word_Problems/528170: A man rode a bicycle for 12 miles and then hiked and additional 8 miles. The total time for the trip was 5 hours. If his rate when riding a bicycle was 10 miles per hour faster than his rate walking, what was each rate?
1 solutions

Answer 349174 by josmiceli(9817) About Me  on 2011-11-08 12:06:59 (Show Source):
You can put this solution on YOUR website!
Let +w+ = rate walking
Let +b+ = rate biking
given:
+b+=+w+%2B+10+ mi/hr
+t%5Bw%5D+%2B+t%5Bb%5D+=5+ hrs
--------------------
biking:
+12+=+%28+w+%2B+10+%29%2At%5Bb%5D+
walking:
+8+=+w%2At%5Bw%5D+
-------------------
By substitution:
+t%5Bb%5D+=+5+-+t%5Bw%5D+
+12+=+%28+w+%2B+10+%29%2A%28+5+-+t%5Bw%5D+%29+
+12+=+5w+%2B+50+-+w%2At%5Bw%5D+-+10t%5Bw%5D+
By substitution again:
+12+=+5w+%2B+50+-+8+-+10t%5Bw%5D+
Substitution again:
+12+=+5w+%2B+50+-+8+-+10%2A%288%2Fw%29+
+80%2Fw+-+5w+=+30+
+80+-+5w%5E2++=+30w+
+w%5E2+%2B+6w+=+16+
Completing the square:
+w%5E2+%2B+6w+%2B+%286%2F2%29%5E2+=+16+%2B+%286%2F2%29%5E2+
+w%5E2+%2B+6w+%2B+9+=+16+%2B+9+
+%28+w+%2B+3+%29%5E2+=+25+
+w+%2B+3+=+5+
+w+=+2+ ( can't use the negative root )
and
+b+=+w+%2B+10+
+b+=+12+
His speed biking was 12 mi/hr
His speed walking was 2 mi/hr


Mixture_Word_Problems/528169: A 50 milliliter solution of acid and water contains 25% acid. How much water do you need to add in order to make a 10% acid solution?
1 solutions

Answer 349163 by josmiceli(9817) About Me  on 2011-11-08 11:43:02 (Show Source):
You can put this solution on YOUR website!
Let +w+ = ml of water needed
given:
+.25%2A50+=+12.5+ ml of acid in 25% solution
---------------
+12.5+%2F+%28+50+%2B+w%29+=+.1+
+12.5+=+.1%2A%28+50+%2B+w+%29+
+12.5+=+5+%2B+.1w+
+.1w+=+12.5+-+5+
+w+=+7.5+%2F+.1+
+w+=+75+
75 ml of water is needed


Probability-and-statistics/528157: in a certain population, 30% of the women are married and 40% of the men are married. what percent of the total population in married? round answer to the nearest tenth of a percent. assume that one woman is married to one man and that each couple resides in this population-
1 solutions

Answer 349162 by josmiceli(9817) About Me  on 2011-11-08 11:33:28 (Show Source):
You can put this solution on YOUR website!
Let +w+ = number of women in population
Let +m+ = number of men in population
Because the married women and married
men are paired with each other, I can say
+.3w+=+.4m+
+m+=+%283%2F4%29%2Aw+
I am asked to find:

+.6w+%2F+1.75w+=+.3428+
To the nearest 1/10 of a percent,
34.3% of the population is married


Linear-systems/528039: How do you solve for y and x ? Like my promblem says solve for y right? So they gave me the promblem 4y + 12 = -3(2x-4), could you help me with this promblem?
1 solutions

Answer 349139 by josmiceli(9817) About Me  on 2011-11-08 03:59:02 (Show Source):
You can put this solution on YOUR website!
What they mean is:
Get y all by itself on one side of the equation
It doesn't really matter which side
---------------------------
You do this by doing the same thing to
both sides of the equation, which leaves
the equation unchanged
----------------------------
+4y+%2B+12+=+-3%282x-4%29+
Subtract 12 from both sides
+4y+=+-3%2A%282x-4%29+-+12+
Now divide both sides by 4
+y+=+%28-3%2F4%29%2A%282x-4%29+-3+
This is OK, but you can finish by
multiplying out
++%28-3%2F4%29%2A%282x-4%29+=+%28-3%2F2%29%2Ax+%2B+3+
Now you have
+y+=+%28-3%2F2%29%2Ax+%2B+3+-3+
+y+=+%28-3%2F2%29%2Ax+


Probability-and-statistics/527740: A card is randomly drawn from a deck of 52 playing cards. What is the probability that it is a King given that the card is Red?
1 solutions

Answer 349014 by josmiceli(9817) About Me  on 2011-11-07 18:12:39 (Show Source):
You can put this solution on YOUR website!
Half of the deck is red: hearts and diamonds
there are 2 Kings that are red, so, given that
the card drawn is red, the probability that it
is a King is 2/26, or 1/13


Miscellaneous_Word_Problems/527745: Juan wants to make a trail mix that contains 40% pecans. He has a bag of trail mix that has only 25% pecans at home and another bag that contains only pecans. How much of each should he mix together to make a 16-oz bag of trail mix that contains 40% pecans?
1 solutions

Answer 349013 by josmiceli(9817) About Me  on 2011-11-07 18:06:17 (Show Source):
You can put this solution on YOUR website!
He ends up with
+.4%2A16+=+6.4+ ounces of pecans
Let +a+ = ounces of 25% mix needed
Let +b+ = ounces of 100% mix needed
given:
(1) +a+%2B+b+=+16+
(2) +.25a+%2B+b+=+6.4+
Multiply both sides of (2) by
+100+. Then multiply both
sides of (1) by 25 and subtract
(1) from (2)
(2) +25a+%2B+100b+=+640+
(1) +-25a+-+25b+=+-400+
+75b+=+240+
+b+=+3.2+
and, since
(1) +a+%2B+b+=+16+
(1) +a+=+12.8+
12.8 ounces of 25% mix are needed
3.2 ounces of 100% mix are needed


Rate-of-work-word-problems/527717: SOPPOSE 4 PEOPLE CAN PAINT A HOUSE IF THEY WORKK 3 DAYS EACH. HOW LONG WOULD IT TAKE OF A CREW OF 5 PEOPLE TO PAINT THE HOUSE ?
1 solutions

Answer 349012 by josmiceli(9817) About Me  on 2011-11-07 17:46:20 (Show Source):
You can put this solution on YOUR website!
I assume all these people work at the same rate
4 people working 3 days can paint 1 house
1 person takes 4 times as long to paint the house, so
1 person takes 12 days to paint the house
5 people will take 1/5 of that time to paint the house
5 people will take 12/5 days, or 2.4 days to paint the house