New!
Get regular updates about newly solved problems
via algebra.com's RSS system.
Recent problems solved by 'josmiceli'
josmiceli answered: 9642 problems
Jump to solutions: 0..29 , 30..59 , 60..89 , 90..119 , 120..149 , 150..179 , 180..209 , 210..239 , 240..269 , 270..299 , 300..329 , 330..359 , 360..389 , 390..419 , 420..449 , 450..479 , 480..509 , 510..539 , 540..569 , 570..599 , 600..629 , 630..659 , 660..689 , 690..719 , 720..749 , 750..779 , 780..809 , 810..839 , 840..869 , 870..899 , 900..929 , 930..959 , 960..989 , 990..1019 , 1020..1049 , 1050..1079 , 1080..1109 , 1110..1139 , 1140..1169 , 1170..1199 , 1200..1229 , 1230..1259 , 1260..1289 , 1290..1319 , 1320..1349 , 1350..1379 , 1380..1409 , 1410..1439 , 1440..1469 , 1470..1499 , 1500..1529 , 1530..1559 , 1560..1589 , 1590..1619 , 1620..1649 , 1650..1679 , 1680..1709 , 1710..1739 , 1740..1769 , 1770..1799 , 1800..1829 , 1830..1859 , 1860..1889 , 1890..1919 , 1920..1949 , 1950..1979 , 1980..2009 , 2010..2039 , 2040..2069 , 2070..2099 , 2100..2129 , 2130..2159 , 2160..2189 , 2190..2219 , 2220..2249 , 2250..2279 , 2280..2309 , 2310..2339 , 2340..2369 , 2370..2399 , 2400..2429 , 2430..2459 , 2460..2489 , 2490..2519 , 2520..2549 , 2550..2579 , 2580..2609 , 2610..2639 , 2640..2669 , 2670..2699 , 2700..2729 , 2730..2759 , 2760..2789 , 2790..2819 , 2820..2849 , 2850..2879 , 2880..2909 , 2910..2939 , 2940..2969 , 2970..2999 , 3000..3029 , 3030..3059 , 3060..3089 , 3090..3119 , 3120..3149 , 3150..3179 , 3180..3209 , 3210..3239 , 3240..3269 , 3270..3299 , 3300..3329 , 3330..3359 , 3360..3389 , 3390..3419 , 3420..3449 , 3450..3479 , 3480..3509 , 3510..3539 , 3540..3569 , 3570..3599 , 3600..3629 , 3630..3659 , 3660..3689 , 3690..3719 , 3720..3749 , 3750..3779 , 3780..3809 , 3810..3839 , 3840..3869 , 3870..3899 , 3900..3929 , 3930..3959 , 3960..3989 , 3990..4019 , 4020..4049 , 4050..4079 , 4080..4109 , 4110..4139 , 4140..4169 , 4170..4199 , 4200..4229 , 4230..4259 , 4260..4289 , 4290..4319 , 4320..4349 , 4350..4379 , 4380..4409 , 4410..4439 , 4440..4469 , 4470..4499 , 4500..4529 , 4530..4559 , 4560..4589 , 4590..4619 , 4620..4649 , 4650..4679 , 4680..4709 , 4710..4739 , 4740..4769 , 4770..4799 , 4800..4829 , 4830..4859 , 4860..4889 , 4890..4919 , 4920..4949 , 4950..4979 , 4980..5009 , 5010..5039 , 5040..5069 , 5070..5099 , 5100..5129 , 5130..5159 , 5160..5189 , 5190..5219 , 5220..5249 , 5250..5279 , 5280..5309 , 5310..5339 , 5340..5369 , 5370..5399 , 5400..5429 , 5430..5459 , 5460..5489 , 5490..5519 , 5520..5549 , 5550..5579 , 5580..5609 , 5610..5639 , 5640..5669 , 5670..5699 , 5700..5729 , 5730..5759 , 5760..5789 , 5790..5819 , 5820..5849 , 5850..5879 , 5880..5909 , 5910..5939 , 5940..5969 , 5970..5999 , 6000..6029 , 6030..6059 , 6060..6089 , 6090..6119 , 6120..6149 , 6150..6179 , 6180..6209 , 6210..6239 , 6240..6269 , 6270..6299 , 6300..6329 , 6330..6359 , 6360..6389 , 6390..6419 , 6420..6449 , 6450..6479 , 6480..6509 , 6510..6539 , 6540..6569 , 6570..6599 , 6600..6629 , 6630..6659 , 6660..6689 , 6690..6719 , 6720..6749 , 6750..6779 , 6780..6809 , 6810..6839 , 6840..6869 , 6870..6899 , 6900..6929 , 6930..6959 , 6960..6989 , 6990..7019 , 7020..7049 , 7050..7079 , 7080..7109 , 7110..7139 , 7140..7169 , 7170..7199 , 7200..7229 , 7230..7259 , 7260..7289 , 7290..7319 , 7320..7349 , 7350..7379 , 7380..7409 , 7410..7439 , 7440..7469 , 7470..7499 , 7500..7529 , 7530..7559 , 7560..7589 , 7590..7619 , 7620..7649 , 7650..7679 , 7680..7709 , 7710..7739 , 7740..7769 , 7770..7799 , 7800..7829 , 7830..7859 , 7860..7889 , 7890..7919 , 7920..7949 , 7950..7979 , 7980..8009 , 8010..8039 , 8040..8069 , 8070..8099 , 8100..8129 , 8130..8159 , 8160..8189 , 8190..8219 , 8220..8249 , 8250..8279 , 8280..8309 , 8310..8339 , 8340..8369 , 8370..8399 , 8400..8429 , 8430..8459 , 8460..8489 , 8490..8519 , 8520..8549 , 8550..8579 , 8580..8609 , 8610..8639 , 8640..8669 , 8670..8699 , 8700..8729 , 8730..8759 , 8760..8789 , 8790..8819 , 8820..8849 , 8850..8879 , 8880..8909 , 8910..8939 , 8940..8969 , 8970..8999 , 9000..9029 , 9030..9059 , 9060..9089 , 9090..9119 , 9120..9149 , 9150..9179 , 9180..9209 , 9210..9239 , 9240..9269 , 9270..9299 , 9300..9329 , 9330..9359 , 9360..9389 , 9390..9419 , 9420..9449 , 9450..9479 , 9480..9509 , 9510..9539 , 9540..9569 , 9570..9599 , 9600..9629 , 9630..9659, >>Next
Average/281164: Helping my son, 7th grade. We need help please.
Q- average for five quizzes is 86. To have an average of 88 or more for six quizzes, what is the lowest score to get on the sixth quiz?
Thanks. 1 solutions
Answer 204257 by josmiceli(9645) on 2010-03-15 16:52:52 (Show Source):
You can put this solution on YOUR website!Let  = lowest score to get on 6th quiz
The average is:
(sum of scores on quizzes)/(number of quizzes) = average grade
For the 1st  quizzes, the average is 
(Sum of scores on 5 quizzes)/5 =
Sum of scores on 5 quizzes = 5*86
Sum of scores on 5 quizzes = 430
and, after taking the 6th quiz:

Multiply both sides by

Must get at least a 98 to average 88 for 6 quizzes
check:

OK
|
Travel_Word_Problems/280838: Train A & B are traveling in the same direction on parallel track. Train A is traveling 80 miles per hour and train B is traveling 90 miles per hour. Train A passes station at 3:10 pm If train B passes same station at 3:22 pm what time will train B catch up to train A 1 solutions
Answer 204088 by josmiceli(9645) on 2010-03-14 21:24:57 (Show Source):
You can put this solution on YOUR website!I have a stopwatch.
I'll start it when the 2nd train, train B, passes the station
Train A passed the station 12 min ago at 3:10
How far did train A get in 12/60 hr? That is his headstart
 mi
Now write equations for each train, with time =  for both,
since I'll stop the stopwatch when they meet

Also note that
Substituting:
(1) 
(2) 
Substituting again:
 hr
B will catch A in 1 hour 36 min, or at 3:22 + 1:36 = 4:58 PM
check:

OK
|
Exponential-and-logarithmic-functions/280462: This one looked easy but it's got me confused please help and thank you.
Use the laws of logarithms to express log base2 6 - log base 2 3 + 2 log base 2 sqrt8 as a single logarithm then evaluate. I got this far log base 2^6 - log base2^3 +2 log base 2 sqrt 8 =log base 2 6/3 sqrt8^2??? help 1 solutions
Answer 203850 by josmiceli(9645) on 2010-03-13 20:34:09 (Show Source):
|
Miscellaneous_Word_Problems/280051: From an original group of boys and girls, twenty girls leave. There are then left two boys for each girl. After this, sixty boys leave. There are then two girls for each boy.The number of girls in the original group was:
(A) 81 (B) 72 (C) 68 (D) 60 (E) 50 1 solutions
Answer 203587 by josmiceli(9645) on 2010-03-12 13:26:52 (Show Source):
You can put this solution on YOUR website!Let  = original number of girls
Let  = original number of boys
given:
Initially, there are:
 in the group
20 girls leave
 in the group
(1) 
Then  boys leave
 in the group
(2) 
(1) and (2) are 2 equations with 2 unknowns, so
it's solvable
(1) 
(1) 
(1) 
(2) 
(2) 
(2) 
Multiply both sides of (1) by  and add equations
(1) 
(2)

The number of girls in the original group was 60
check answer:
(1)

(2) 
(2)

OK
|
real-numbers/280060: Two trains, one traveling 10 km/h faster than the other, leave the same station at the same time, one
traveling east and one traveling west. At the end of 6 hours, they are 540 km apart. How far does each train travel? 1 solutions
Answer 203559 by josmiceli(9645) on 2010-03-12 11:11:19 (Show Source):
You can put this solution on YOUR website!It's the same problem if you think of 1 train
as being stationary, and the other moving at
their added speeds
In  hrs:
 km/hr is their added speeds
Their speeds are  and

In  hrs, 1st train goes
 km
and the 2nd train goes
 km
check:

OK
|
real-numbers/280061: A car traveling at a rate of 30 km/h left Gander. A second car left Gander 1 hour later. At what rate
must the second car travel to catch up with the first in 3 hours? 1 solutions
Answer 203535 by josmiceli(9645) on 2010-03-12 10:20:41 (Show Source):
You can put this solution on YOUR website!Start a stopwatch when the 2nd car leaves Gander
When I start the stopwatch, the 1st car has a
 mile head start
When I stop the stopwatch, they both will have
driven for the same time, which is  hrs
1st car:
 mi
2nd car:
 mi
and

The 2nd car must drive 40 mi/hr to catch the 1st car
|
Finance/280077: I just need to set this up: I invested X at 10%, and 2X at 12%, for a total interest of 2890. What is X? 1 solutions
Answer 203529 by josmiceli(9645) on 2010-03-12 10:09:18 (Show Source):
|
Finance/280100: John put $40 into his investment club every month for a year at a 7% annual interest rate. Interest is calculated once at the end of the year. How much money was in his account at the end of the year? 1 solutions
Answer 203522 by josmiceli(9645) on 2010-03-12 10:02:08 (Show Source):
|
Equations/280103: There are 480 dishes that need to be rinsed. John can rinse them in 80 minutes by himself. It will take his friend Bob 120 minutes to rinse these dishes. How long will it take them if they rinse these 480 dishes together? 1 solutions
Answer 203521 by josmiceli(9645) on 2010-03-12 09:58:25 (Show Source):
You can put this solution on YOUR website!The number  does not need to enter the calculations
Just call washing that many dishes 1 job
In words:
(John's rate of working) + (Bob's rate of working) = rate of working together
John's rate = 1 job/80 min
Bob's rate = 1 job/120 min

Multiply both sides by

It will take them 48 minutes working together
|
Equations/280104: There is a sales tax of $22 on an item that costs $275 before tax. A second item costs $87.50 before tax. What is the sales tax on the second item? 1 solutions
Answer 203519 by josmiceli(9645) on 2010-03-12 09:48:58 (Show Source):
You can put this solution on YOUR website!The sales tax will be the same percent rate for both items.
For the 1st item, $22 is what percent of $275?
 = 8%
For the 2nd item,

$7 is the sales tax
|
Linear-systems/280099: train A is traveling at 60 mph and train B at 80 mph. train A passes the station at 810 and train B at 825 at what time will train B catch train A? 1 solutions
Answer 203518 by josmiceli(9645) on 2010-03-12 09:44:23 (Show Source):
You can put this solution on YOUR website!Train A has a 15 minute head start over B if you consider
the station as the starting point. In that time, A has gone
 miles.
Assume I have a stopwatch. I'll start it when B reaches the station
If I stop it when B catches A, both trains will have been moving
for the same length of time, which I'll call 
given:
 mi/hr
 mi/hr
 mi
----------------
Now I can write equations for both trains

By substitution,
 hr
Train B will catch train A in 45 min, or at 8:25 + 45 = 9:05
check answer:
 mi
and
 mi
OK
|
Rational-functions/280098: can you help me with this problem? I don't understand it.
(-5+2i)-(9+3i) 1 solutions
Answer 203515 by josmiceli(9645) on 2010-03-12 09:18:43 (Show Source):
You can put this solution on YOUR website!You are asked to subtract 2 complex numbers. You have to subtract the real parts
separately from the imaginary parts. I don't know how far you are with
imaginary numbers, but subtract them like this:

Now subtract the real parts

The answer is:
|
Travel_Word_Problems/280092: The separate sections of rail on a railroad track are 30 ft. long. As the train passes over the point where the sections are joined, there is an audible click. By what fraction must the number of clicks in a minute be multiplied to find the speed of the train in miles per hour? 1 solutions
Answer 203514 by josmiceli(9645) on 2010-03-12 09:13:20 (Show Source):
You can put this solution on YOUR website!There are  ft in a mile
You will hear  clicks/mile
If the train's speed was  mile/min, that is  miles/hr
So,  clicks/min means the train's speed is  miles/hr
Therefore,  x clicks/min gives the train's
speed in miles/hr
|
Miscellaneous_Word_Problems/280081: A piece of string 15 inches long is cut into four pieces. If each successive piece is half as long as the preceding piece, then the length of the first piece, in inches, is:
(A) 6 (B) 7 (C) 8 (D) 9 (E) 10 1 solutions
Answer 203502 by josmiceli(9645) on 2010-03-12 08:18:02 (Show Source):
|
Miscellaneous_Word_Problems/280080: Sales of cassette tapes of music decreased by 7% per year for 3 years. The percent that best approximates the total percent that sales of cassette tapes of music decreased during this time period is:
(A) 80.4% (B) 79% (C) 34.3% (D) 21% (E) 19.6% 1 solutions
Answer 203501 by josmiceli(9645) on 2010-03-12 08:08:44 (Show Source):
|
Percentage-and-ratio-word-problems/279975: An instrument store gives a 10% discount to all students off the original cost of an instrument. During a back to school sale an additional 15% is taken off the discounted price. Julie, a student at the local high school, purchases a flute for $306. How much did it originally cost? 1 solutions
Answer 203463 by josmiceli(9645) on 2010-03-11 22:06:31 (Show Source):
|
Mixture_Word_Problems/279858: A 10% salt solution is mixed with an 18% salt solution to obtain a 32 oz 15% solution. How many ounces of each are needed? 1 solutions
Answer 203402 by josmiceli(9645) on 2010-03-11 18:51:03 (Show Source):
You can put this solution on YOUR website!Let  = ounces of 10% solution needed
Let  = ounces of 18% solution needed
given:
(1)  ounces
(2) 
(2) 
-------------------
Multiply both sides of (2) by 
(2) 
Multiply both sides of (1) by 
and subtract from (2)
(2) 
(1)

and, since

12 ounces of 10% solution and 20 ounces of 18% solution are needed
check:
(2)

OK
|
Money_Word_Problems/279764: I get paid monthly. I want to know how to figure out how much I earn hourly.
Thank you. 1 solutions
Answer 203351 by josmiceli(9645) on 2010-03-11 14:35:30 (Show Source):
You can put this solution on YOUR website!There are 4 weeks in a month, and most people work 5 days/week
and 40 hours/day
 days/month of work
Let  = monthly pay in dollars
(x/1 month ) x (1 month/4 weeks) x (1 week/5 days) x (1 day/40 hours) = x/(4 x 5 x 40) = x/800
Hourly, you earn (monthly pay)/800
If you earned $4,000/month, you make
 = $5/hr
|
|