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Rate-of-work-word-problems/625675: I apologize if this is the wrong topic selection for my question. It was the best I could find. If I should ask elsewhere, could you tell me which topic I should choose?
My question is: 'Person A can complete a job in four hours. Person b can complete the job in 6 hours. Working at the same rate, How many hours will it take both of them to complete the job?'
I don't believe it is as easy as just adding the two together. Is it just finding the mean of the two working times; (6 hours + 4 hours)/2 ?
1 solutions

Answer 393700 by sudhanshu_kmr(1152) About Me  on 2012-07-03 13:15:02 (Show Source):
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Person A can complete work in 1 hour = 1/4 part
Person B can complete work in 1 hour = 1/6 part
Total work that can be done in 1 hour if both work together = 1/4 +1/6

= 5/12 part.
Time required to complete the work = 12/5 hours
By formula u can solve in this way : A*B/ (A+B)
= 4*6 /(4+6)
= 24/10 = 12/5 hours.
I hope it will help u to understand the solution.
Feel free to ask if any doubt...


Permutations/625512: if there are 6 students who all want to be in a group of 3 people, how many groups can be chosen?
1 solutions

Answer 393692 by sudhanshu_kmr(1152) About Me  on 2012-07-03 13:04:34 (Show Source):
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Number of ways to select a group of 3 people = 6C3 = 20




Permutations/624977: A single die is rolled five times, and the number of fours that come up is tallied. Find the probability of getting exactly two fours. (I want to know how to set it up to get me answer and the answer so that i can fill in the numbers that leads to that answer)
1 solutions

Answer 393464 by sudhanshu_kmr(1152) About Me  on 2012-07-02 08:51:14 (Show Source):
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Probability of getting 4 in single throw = 1/6
so, probability of net getting 4 in single throw = 5/6

probability of getting exactly two fours in five throw = 5C2* (1/6)^2 * (5/6)^3
( Binomial probability )
= 10 * 5^3 / (6^5)


I hope it will help you to understand the concept, feel free to ask if any doubt....


Rectangles/621578: The width of a rectangle is x inches long. The length of that rectangle is 5 inches less than twice the width. If the perimeter measures 26 inches, what is the measure of the length and width of the rectangle. Show all the work and the alegbra you used to solve this problem.

I am having a hard time. I'm not even sure where to start with this.
If 26 inches is the whole measurement and the length is 5 inches less than the width... Then would it be worked as this .... 5-x=26 ??? That doesn't seem right because once you work the problem it would be
5-x=26
+5 +5
x=31
31 could not be the measure of the length because that is greater than 26, which is the whole measurement of the unit.
Help please.
1 solutions

Answer 390834 by sudhanshu_kmr(1152) About Me  on 2012-06-18 00:52:20 (Show Source):
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width = x
length = 2*x-5
perimeter = 2*(x + 2x-5)

According to question..
2*(x+2x-5) = 26
=> 6x -10 =26
=> x = 36/6 = 6
width = 6 inches
length = 7 inches.
if any doubt, feel free to contact ....


Probability-and-statistics/617231: Please help:
The tiles A,B,G,I,M,R, and S of a word game are placed face down on a table. If two tiles are randomly chosen, one at a time. Find the probability:
a)P(R,then S) no replacement occurs
b)P(2 consonants) if replacement occurs
c)P(2 vowels) if no replacemnet occurs
1 solutions

Answer 388236 by sudhanshu_kmr(1152) About Me  on 2012-06-03 04:24:46 (Show Source):
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Total = 7, vowel =2, consonant = 5
a) 1/7 * 1/6 = 1/42

b) 5/7 * 5/7 = 25/49

c) 2/7 * 1/6 = 1/21


Permutations/617233: Please help solve Thanks
Each question on a five-question multiple choice quiz has answer choices labeled A,B,C,and D. How many different ways can a student answer the five questions?
Is the answer 5*4=20 or 5P4=120 or ????
1 solutions

Answer 388234 by sudhanshu_kmr(1152) About Me  on 2012-06-03 04:17:31 (Show Source):
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A student can answer a question in 4 ways.
Total number of ways to answer 5 questions = 4 * 4 * 4 * 4 * 4 = 4^5 = 1024

If any doubt, feel free to contact by mail...


Permutations/610198: Student ID codes consist of uppercase letters as well as the digits 0 through 9.
How many 2-character ID codes are possible if at least one of the digits must be a number?
1 solutions

Answer 384436 by sudhanshu_kmr(1152) About Me  on 2012-05-13 16:01:14 (Show Source):
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Case 1: Both digits are numbers.

Number of possible ID codes = 10^2 = 100 ( 00,01,.... to 99)
Case 2: First digit is number and second is a letter.
Number of possible ID codes = 10*26 = 260 [ ex- 9A, 8D,. ]
Case 3: First digit is letter and second is a number.
Number of possible ID codes = 26*10 = 260 [ ex- A6, D7,. ]

Total number of possible ID codes = 100+ 260 +260 = 620

If any doubt, feel free to contact my mail. sudhanshu.cochin@gmail.com



test/610306: two similar cylindrical juice containers have a scale factor of 2:3. To make juice in the smaller container, you use 1/2 cup of concentated juice and fill the rest with water. Find the amount of concentrated juice needed to make juice in the larger container. (Hint: Start by finding the ratio of the volumes of the containers.)
Please help me with this. I found the ratio of the volumes of the containers, which is 8:27, but I'm lost at what to do next. Please help me and explain. Thanks in advance!
1 solutions

Answer 384432 by sudhanshu_kmr(1152) About Me  on 2012-05-13 15:45:18 (Show Source):
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Ratio of the volumes of the containers is 8:27.
so, volume are 8x and 27x.

amount of concentrate juice for 8x is 1/2 cup.
then, amount of concentrate juice for 1x is 1/(2*8) cup.

and amount of concentrate juice for 27x is [ 1/(2*8)]*27 cup.

answer : 27/16 cup



Permutations/593709: In how many ways can a six-member committee form a subcommittee with at least two members?
I thought it would be 2^6 - 2 but the answer is suppose to be 57.
1 solutions

Answer 376540 by sudhanshu_kmr(1152) About Me  on 2012-03-31 22:58:35 (Show Source):
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Number of ways to form subcommittee : 6C2 + 6C3 + 6C4 + 6C5 + 6C6
( number of members can be 2,3,4, 5 or 6)
= 15 + 20 + 15 + 6 + 1
= 57


Permutations/593937: How to find the number of ways 12 students can be divided into 2 groups of 8 students and 4 students
1 solutions

Answer 376539 by sudhanshu_kmr(1152) About Me  on 2012-03-31 22:49:34 (Show Source):
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number of ways = 12C8 * 4C4

if any doubt, feel free to ask...


Permutations/588548: To make a two letter code the first letter is chosen from the set of vowels and the second letter is chosen from the 26 letters of the alphabet.How many of this codes, (a)end with D. (b)start with an E and end with a D. (c)start with an E or end with a D. (d)start and end with the same letter.
1 solutions

Answer 374538 by sudhanshu_kmr(1152) About Me  on 2012-03-18 23:56:28 (Show Source):
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a) 5
b) 1
c)26 + 5 - 1 = 30
d)5


Travel_Word_Problems/586130: Please help me solve this problem.
Thank you,
David R
jody is driving at a constant rate. she passes a milepost that displays a two-digit number. exactly on hour later, she passes a second milepost that displays the same two digits in the reverse order. one hour later, she passes a third milepost with the original two digits separated by a zero. what is her rate in miles per hour?
1 solutions

Answer 373689 by sudhanshu_kmr(1152) About Me  on 2012-03-13 14:07:32 (Show Source):
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Let assume first number is xy ie. 10x+y
second number is 10y+x,
third number is 100x+ y

Difference between first and second = distance between second and third.

=> 10y +x -(10x+y) = 100x+y - (10y+x)

after solving this we get, y = 6x

so, only possible value of x is 1, otherwise y will become two digit number.

so, numbers are 16, 61 and 106.

speed = 61-16 = 45 miles per hour.

if any doubt, feel free to ask....



Permutations/585884: The digits of the locker combination consist of 3 one digit numbers, 1-9. If the digits are not repeated, what is the probabiliity of the combination being 1, 2, 3?
1 solutions

Answer 373529 by sudhanshu_kmr(1152) About Me  on 2012-03-12 14:44:06 (Show Source):
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number of total possible combination = 9*8*7
probability of combination being 1,2,3 is : 1/(9*8*7)


Probability-and-statistics/585877: A quiz has 5 multiple choice questions. There are 3 choices for each question, with only one correct answer. Thus the probability of guessing the correct answer for any question is 1/3. A student guesses on all 5 questions. What is the probability they get exactly 3 correct? Give answer to the nearest thousandth as a decimal
1 solutions

Answer 373527 by sudhanshu_kmr(1152) About Me  on 2012-03-12 14:40:59 (Show Source):
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probability of correct answer = 1/3

probability of wrong answer = 2/3
By using Binomial probability...
probability of exactly 3 correct answer = 5C3 *(1/3)^3 * (2/3)^2


if any doubt, feel free to ask......


Probability-and-statistics/581917: For the daily lottery game in a lottery, players select three numbers between 0 and 9. A number cannot be selected more than once, so a winning ticket could be, 203 or 302. 222, or 330 is not allowed. Purchasing one ticket allows you to select one set of numbers. How many different outcomes (three digit numbers) are possible?
1 solutions

Answer 371864 by sudhanshu_kmr(1152) About Me  on 2012-03-04 14:33:11 (Show Source):
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If zero at first place is allowed then, total outcomes = 10*9*8 = 720

otherwise, total outcomes = 9 * 9 * 8 = 648


if any doubt, feel free to ask..


Permutations/581624: In how many ways can four married couples attending a concert be seated in a row of eight seats if:
(a) There are no restrictions?
(b) Each married couple is seated together?
(c) The members of each sex are seated together?
1 solutions

Answer 371862 by sudhanshu_kmr(1152) About Me  on 2012-03-04 14:27:46 (Show Source):
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Total number of people = 8
a) 8!
b) 2* 2 * 2 * 2 * 4!
c) 4! * 4! * 2!

if any doubt, feel free to ask..


Permutations/580258: Three men and ten women are to line up for a picture with the three men in the middle. How many ways can this be done? (Assume there are five women on each side of the group of men)
The answer is 21772800 but i have no idea how to attain it. Thanks!
1 solutions

Answer 371277 by sudhanshu_kmr(1152) About Me  on 2012-02-29 22:52:28 (Show Source):
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Number of ways to arrange 10 women = 10! = 3628800
Number of ways to arrange 3 men = 3! =6

total number of ways = 362880 * 6 = 21772800


If any doubt, feel free to contact ...
http://www.algebra.com/tutors/aboutme.mpl?userid=sudhanshu_kmr


Probability-and-statistics/576800: Hi,
There are 12 red beads and 12 green beads. Choose 4 beads randomly.
1. What are the chances that 4 out of 4 beads will be red?
(12/24)^4 seems correct. But why wouldn't 12C4/24C4 be correct? I'm having trouble understanding when to use which formula.
2. What are the chances that 3 out of 4 beads will be red?
12C3+12C4/24C4 <--- is this correct?

Thanks!
1 solutions

Answer 370003 by sudhanshu_kmr(1152) About Me  on 2012-02-23 04:01:53 (Show Source):
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1. 12C4 / 24C4
2. [ 12C3 * 12C1] /24C4

if any doubt, feel free to ask...



Permutations/576127: Mia has four math books, three novels and two books of poetry. She wants to arrange them on her shelf so that all the math books are together on the left end of the shelf, all the novels are together in the middle, and the books of poetry are together on the right end. How many possible arrangements of the books are possible?

1 solutions

Answer 370002 by sudhanshu_kmr(1152) About Me  on 2012-02-23 03:57:57 (Show Source):
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Number of possible arrangements = 4! * 3! * 2! = 24*6*2 = 288


Probability-and-statistics/574863: If a person is randomly selected, find the probability that his/her birthday is in May. Ignore leap years. Assume that all days of the year are equally likely for a given birth.
My answer = 1/365 or 1/12?
Thank you very much!
1 solutions

Answer 369357 by sudhanshu_kmr(1152) About Me  on 2012-02-19 20:28:09 (Show Source):
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probability = 31/365


Permutations/574472: Please help me solving this problem.
A carton of 24 eggs contains one that is spoiled. In how many ways can people chose 3 of these eggs and gets one that is spoiled?
Thank you.
1 solutions

Answer 369267 by sudhanshu_kmr(1152) About Me  on 2012-02-19 05:16:39 (Show Source):
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Out of 24 one is spoiled, 23 is not spoiled.
Number of ways = 23C2 * 1C1 = 253

if any doubt, feel free to contact....


Permutations/574411: A telephone company wants to create as
many 7-digit phone numbers as possible
without changing the first 3 digits. How
many phone numbers can be created?
1 solutions

Answer 369266 by sudhanshu_kmr(1152) About Me  on 2012-02-19 05:09:01 (Show Source):
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According to question first 3 digits are fixed.
Number of ways to create 4 digit numbers = 10* 10*10*10 = 10000
(repetition of digits are allowed on phone number)

if any doubt, feel free to contact....


Permutations/560066: If I have 6 objects labeled A-F and I need to know how many different combinations that can be made but each combination MUST include object A, how would I figure this out? And the combinations aren't limited to having to have 6 letters...for example, A by itself is a combination. AB, AC,AD, and DA,EA,FA are all combinations. Any help?
1 solutions

Answer 363932 by sudhanshu_kmr(1152) About Me  on 2012-01-21 23:10:18 (Show Source):
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Number of combinations having only one object = 1C1 = 1 i.e A
because every combination must include object A.

number of combinations having two objects = 5C1 = 5
as we have to choose another 1 out of other 5 objects, A has been chosen already.

similarly,
number of combinations having three objects = 5C2 = 10


total number of possible combinations = 1 +5C1 + 5C2 + 5C3 +5C4 +5C5


if any doubt, feel free to ask....


Permutations/556801: there is a game I play There are 6 soccer games. each game has a win draw win result. So it can be either a win for team a draw or win for team b.
Now with 6 games and 3 possibilities in each game, how many combinations is possible for all 6 games
1 solutions

Answer 362488 by sudhanshu_kmr(1152) About Me  on 2012-01-14 12:55:58 (Show Source):
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Use formula : [n+r-1]C[r-1]
n+r+1 = 8, r-1 = 2
Total number of possible combinations = 8C2 = 28

if any doubt, feel free to contact by mail..


Permutations/550645: **THERE are 14 boys and 16 girls in Mr. Heath's class. The name of each student in the class was written on a slip of paper. Mr. Heath will draw a name from the bag, and WITHOUT replacing it, draw a second name. What is the probability that he will pick a boy followed by a girl?
a.1/124
b.112/435
c.2/3
d.435/443
1 solutions

Answer 359358 by sudhanshu_kmr(1152) About Me  on 2011-12-30 12:09:36 (Show Source):
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14+16 = 30
probability = (14/30) * (16/29) = 112/435
ans. b


Probability-and-statistics/551072: The probability that A can solve a problem is 4/5, that B can solve it is 2/3 and that C can solve it is 3/7. If all of them try independently, find the probability that the problem will be solved.
-------
i believe the shortcut would be
1 - P(a fails to solve)P(b fails to solve)P(c fails to solve) = 1 - (4/5)(2/3)(3/7) = 0.96
however what i want to ask is the LONG version on how i can arrive at 0.96.
thanks!
1 solutions

Answer 359357 by sudhanshu_kmr(1152) About Me  on 2011-12-30 12:02:47 (Show Source):
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probability that problem will not be solved by anyone = (1-4/5)(1-2/3)(1-3/7)
= 1/5 * 1/3 * 4/7 = 4/105
probability that problem will be solved = 1 - 4/105 = 101/105



Permutations/551002: A class consists of 6 girls and 10 boys. If a committee of 3 is chosen at random from the class,
find the probability that (i) 3 boys are selected, (ii) exactly 2 boys are selected, (iii) at least one
boy is selected, (iv) exactly 2 girls are selected.
I want to know the answer to subsection (ii) and how it is different from subsection (i)

1 solutions

Answer 359314 by sudhanshu_kmr(1152) About Me  on 2011-12-30 05:21:18 (Show Source):
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Total number of possible committee = 16C3

i) number of possible committee having 3 boys = 10C3
probability = 10C3 /16C3

ii) number of possible committee having exactly 2 boys = 10C2* 6C1
probability = 10C2*6C1 /16C3


iii) number of possible committee having at least one boy = 16C3 - 6C3
probability = [ 16C3 - 6C3 ]/16C3



iv) number of possible committee having exactly 2 girls = 6C2* 10C1
probability = 6C2*10C1 /16C3


If any doubt, feel free to contact..



Miscellaneous_Word_Problems/550854: Could you please help me with this problem?: Shawna liked to jog late at night. One night she noticed an unusual phenomenon. As she jogged, dogs would hear her and bark. Then in another 15 seconds, each barking dog would "inspire" two more dogs to start barking. Of course, long after Shawna passed the first dog, it continued to bark, as dogs are inclined to do. How many dogs were barking three minutes after Shawna passed the first dog?
1 solutions

Answer 359146 by sudhanshu_kmr(1152) About Me  on 2011-12-29 12:17:58 (Show Source):
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number of dogs will increase as
1, 3, 9, 27 .... and so on

3*60 = 180 , 180/15 = 12

total number of dogs = 12 th term the series of 1,3,9,27

total number of dogs = 3^11



Permutations/550826: seven women and three men on a committee. Committee is to consist of four. how many different ways can the committee be selected if:
A= there are no restrictions.
B= A particular person must be on the committee.
C= A particular person must not be on the committee.
D= the committee must consist of one woman and three men.
E= the committee must have more woman than men

1 solutions

Answer 359144 by sudhanshu_kmr(1152) About Me  on 2011-12-29 12:08:48 (Show Source):
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A. 10C4

B. 9C3

C. 9C4

D. 7C1 * 3C3 = 7

E. 7C4 + 7C3* 3C1


if any doubt,feel free to contact..


Permutations/549499: Boomboom joined Scout Jamboree. Every scout was said to handshake with
each other. Some of them did not do. The total number of handshakes was 7.
Find the minimum number of handshakes which were not done?
1 solutions

Answer 358529 by sudhanshu_kmr(1152) About Me  on 2011-12-26 00:00:00 (Show Source):
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If total number of persons = n
number of handshakes = nC2
For 2,3,4, 5, 6... people number of handshakes will be 1,3,6,10,15.... respectively.
Because here 10 is smallest value greater than 7.
minimum number of handshakes which were not done = 10-7 = 3

If any doubt, feel free to contact.






Permutations/544764: A ship carries four signal flags, each a different color. The order in which the flags are hoisted on the flag pole constitutes a signal.
a) How many different signals can be made when all four flags are raised?
b) How many different signals can be made using three flags?
c) How many different signals can be made in total using any number of the four flags?
1 solutions

Answer 355329 by sudhanshu_kmr(1152) About Me  on 2011-12-10 05:28:10 (Show Source):
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a) 4! = 24
b) 4P3 = 24
c) 4P1+ 4P2 + 4P3 + 4P4 = 4 + 12 + 24 + 24 = 64

if any doubt, feel free to contact.