If k is divisible by 2, 3, and 15, which of the following is also divisible by these numbers?
(A) k + 5
(B) k + 15
(C) k + 20
(D) k + 30
(E) k + 45
divisible by 2, 3, and 15
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- sanju09
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- neelgandham
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k is divisible by 2, 3, and 15, so for k + x to be divisible by these numbers x should also be divisible by all these numbers.From the options, only 20 and 30 are divisible by 2, and only 30 is divisible by 3(between 20 and 30), so Option D - k+30sanju09 wrote:If k is divisible by 2, 3, and 15, which of the following is also divisible by these numbers?
(A) k + 5
(B) k + 15
(C) k + 20
(D) k + 30
(E) k + 45
Last edited by neelgandham on Thu Nov 17, 2011 3:22 am, edited 1 time in total.
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- kmittal82
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I'm sure there's an "algebraic" way of doing this, but its much simpler to test it with k = 30 (which is the lowest k divisible by 2,3 and 15)
Plugging k = 30, (D) is the only option which is still divisible by 2,3 and 15
Plugging k = 30, (D) is the only option which is still divisible by 2,3 and 15
- Abhishek009
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2 , 3 and 15 are co prime numbers...sanju09 wrote:If k is divisible by 2, 3, and 15, which of the following is also divisible by these numbers?
(A) k + 5
(B) k + 15
(C) k + 20
(D) k + 30
(E) k + 45
Now to find the least common no which is divisible by 2, 3 and 15 we take the LCM of the numbers which is 30....
Hence k = 30
Again we need to find the number , divisible by the no's will be by checking the options individually -
A. 30 +5 which is not divisible by 2 and 3
B. 30+15 which is not divisible by 2 and 3
C. 30+20 which is not divisible by 2 and 3
D. 30 + 30 which is divisible by 2 and 3 and 15...
Hence answer will be D..
Abhishek