Search found 18 matches
Number of words
Eight different letters of an alphabet are given.
Words of four letters from these are formed.
The number of such words with atleast one letter repeated is:
(a) \binom{8}{4}-^8P_4
(b) 8^4+\binom{8}{4}
(c) 8^4-^8P_4
(d) 8^4-\binom{8}{4}
- by rahul goyal
Thu Aug 12, 2010 1:53 am- Forum: Problem Solving
- Topic: Number of words
- Replies: 1
- Views: 894
OG 12 ed: page180 q. 195 A store currently charges the same price for each towel that is sells. If the current price of each towel were to be increased by $1, 10 fewer of the towels could be bought for $ 120, excluding sales tax. What is the current price of each towel A. $1 B. $2 C. $3 D. $4 5. $1...
- by rahul goyal
Wed Aug 11, 2010 10:56 pm- Forum: Problem Solving
- Topic: OG 12 ed: towels question
- Replies: 14
- Views: 3805
there are a few ways to solve this problem 1. using combinatorics concept there are 6!/(2!4!)=15 ways of selecting group of 2 people from this group six workers next, using the "reducing the pool concept" ... if Jose and Joshua MUST be chosen, then there is only way to do that i.e. 1 * 1 ...
- by rahul goyal
Wed Aug 11, 2010 10:30 pm- Forum: Problem Solving
- Topic: Probability
- Replies: 5
- Views: 7095
1.If N is a perfect square, then the number of factors of N will ALWAYS be an ODD number. 2.If N is a NON-perfect square, then the number of factors of N will ALWAYS be an EVEN number. Are the above 2 properties correct? 1.If N is a positive integer which is a perfect square, then the number of fac...
- by rahul goyal
Wed Aug 11, 2010 10:11 pm- Forum: Problem Solving
- Topic: Number Properties
- Replies: 9
- Views: 1448
Thank you selango.we have to answer quickly in this way.selango wrote:C=k/R
4=K/R
C=k/(1/3*R)
C=3*k/R=3*4=12
- by rahul goyal
Wed Aug 11, 2010 9:59 pm- Forum: Problem Solving
- Topic: Proportaions
- Replies: 3
- Views: 1055
A machine requires 480 ounces of oil everyday, and it is given a mixture of oil A and oil B. Oil A consists of 5% special additives while oil B consists of 8% special additives. If the machine needs exactly 30 ounces of the special additives to ensure smooth operation, then how much of oil A, in ou...
- by rahul goyal
Wed Aug 11, 2010 12:21 am- Forum: Problem Solving
- Topic: Percentages
- Replies: 2
- Views: 959
Find the exponent of 3 in 100!. please help me to solve it............ Divide 100 by powers of 3 to get the exponent of 3 in 100! 100/3 = 33 100/9 = 11 100/27 = 3 100/81 = 1 Hence exponent of 3 = 33+11+3+1 = 48 Hope this helps!! thank u very much .......i understood how to solve it.......you are si...
- by rahul goyal
Tue Aug 10, 2010 11:59 pm- Forum: Problem Solving
- Topic: how to solve these ps question
- Replies: 6
- Views: 1100
I just got this problem on MGMAT CAT 3, the official answer was B, which I disagree with. Question: "It takes the high-speed train x hours to travel the z miles from Town A to Town B at a constant rate, while it takes the regular train y hours to travel the same distance at a constant rate. If...
- by rahul goyal
Tue Aug 10, 2010 11:50 pm- Forum: Problem Solving
- Topic: Rate Problem
- Replies: 5
- Views: 6247
Expected number
4 bad apples accidentally got mixed up with 20 good apples.
In a draw of 2 apples at random, expected number of bad apples is
(a) 1
(b) 2/3
(c) 1/3
(d)1/6
- by rahul goyal
Tue Aug 10, 2010 10:02 pm- Forum: Problem Solving
- Topic: Expected number
- Replies: 1
- Views: 1270
The ratio, by volume, of acid to base to water in a certain solution is 4:15:20. The solution is altered so that the ratio of acid to base is 3:5 and the ratio of acid to water remains same. If the solution initially contained 30mm of base, what is the minimum amount of water that could be added in...
- by rahul goyal
Tue Aug 10, 2010 9:38 pm- Forum: Problem Solving
- Topic: Ratios and Mixtures
- Replies: 10
- Views: 4598
Thank you selango it is better way.selango wrote:ax^2+kx+n=6x^2-11x-10
a=6
k=-11
n=-10
a-n+k=6+10-11=5
Pick A
- by rahul goyal
Tue Aug 10, 2010 2:06 am- Forum: Problem Solving
- Topic: value of a - n + k?
- Replies: 3
- Views: 1067
Good question. I learned that, for these, you should break the non-prime bases down to primes to make all of the bases consistent: 5^21 * (2^2)^11 = 2 * (2*5)^n 5^21 * 2^22 = 2 * 2^n * 5^n Then because the only way to get 5^21 is through that 5 term, n would be 21, and it works because there are 22...
- by rahul goyal
Tue Aug 10, 2010 1:47 am- Forum: Problem Solving
- Topic: Exponents
- Replies: 4
- Views: 1182
Thanks Nithi.But give the explanation for clear idea.nithi_mystics wrote:66 balls
21 white + 22 green + 23 blue or
21 white + 22 blue + 23 green
- by rahul goyal
Mon Aug 09, 2010 11:57 pm- Forum: Problem Solving
- Topic: 21 white balls, 24 green balls and 32 blue balls
- Replies: 4
- Views: 1472
can you please explain how is OAP 70 The angle at the centre of a circle is twice the angle at the circumference if both angles stand on the same arc. This is called the Angle at Centre Theorem. Refer to this link for proof: http://www.mathsteacher.com.au/year10/ch06_geometry/08_angle_at_centre/cir...
- by rahul goyal
Mon Aug 09, 2010 11:46 pm- Forum: Problem Solving
- Topic: Gmat prep geometry
- Replies: 8
- Views: 1305
Help me, for solve this problem
Two consecutive sides of a parallelogram are 4x+5y=0 and 7x+2y=0.
If the equation to one diagonal is 11x+7y=9,
Then the equation of the other diagonal is:
(a) x+2y=0
(b) 2x+y=0
(c) x-y=0
(d) none of these
- by rahul goyal
Mon Aug 09, 2010 8:57 pm- Forum: Problem Solving
- Topic: Help me, for solve this problem
- Replies: 2
- Views: 1030