GRE Quiz | GRE Quantitative 2 | Question 16

How many three digit number which are divisible by 6 and 3 both?

(A) 300
(B) 299
(C) 150
(D) 149
(E) 124

Answer: (C)
Explanation: Divisibility rule by 6: the number must be an even number and sum of digit must be divisible by 3.

The first number which is divisible by 6 is 102 and the last number is 996. Applying arithmetic formula for finding number of terms with common difference (d) 6, first term(A₁) 102 and last term(A_n) 996:

An = A1 + (n - 1)*d
996 = 102 + (n - 1)*6
n-1 = 894 / 6 = 149
n = 150 

So, option (C) is correct.
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