PS Set 4

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PS Set 4

by radhika1306 » Tue Oct 16, 2007 2:08 pm
If an integer n is to be chosen at random from the integers 1 to 96, inclusive, what is the probability that n(n + 1)(n + 2) will be divisible by 8?
A. 1/4
B. 3/8
C. 1/2
D. 5/8
E. 3/4

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by dpatwa » Tue Oct 16, 2007 6:57 pm
What's the answer? The other linked post does not give the OA.

I think it's 3/8.

The n(n+1)(n+2) will be divisible by 8 for three consecutive numbers, ie 6,7,8. Between 1 and 96, there are 12 numbers that are a multiple of 8. Given the expression, there will be 12*3 numbers that will be divisible by 8, so we get 36/96=3/8.

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by ri2007 » Thu Oct 18, 2007 1:07 pm
Can u pls confirm the answer. I feel the answer should be 1/2

n(n+1)(n+2) will be divisible for any value of n, where n is even.

Since there are 48 even numbers from 1 to 96 and a total of 96 numbers ans is 48/96 = 1/2

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by ri2007 » Thu Oct 18, 2007 1:08 pm
Can u pls confirm the answer. I feel the answer should be 1/2

n(n+1)(n+2) will be divisible for any value of n, where n is even.

Since there are 48 even numbers from 1 to 96 and a total of 96 numbers ans is 48/96 = 1/2