If k is the greatest positive integer such that 3^k is a divisor of 15! then k =	Answers.
A) 3	B) 4	C) 5	D) 6	E) 7

Rationale: for solving this type of tasks we can use such approach 15 / 3 = 5 15 / 3 ^ 2 = 1 and remainder and 3 ^ 3 is more than 15 so we stop on second exponent 5 + 1 = 6 so maximum value of k = 6 and answer is d
Answer: D