gmatophobia wrote:
PS Question 2 - Nov 23
If integer k is equal to the sum of all even multiples of 15 between 295 and 615, what is the greatest prime factor of k?
A. 5
B. 7
C. 11
D. 13
E. 17
Source: Manhattan | Difficulty: Hard
Even multiples of 15 from 295 to 615 are 300, 330, 360 .... 570, 600
Total numbers = (600-300)/30 + 1 = 11
Sum = 11/2 (300+600) = 11/2 * 900 = 11*450 = 11*9*25*2 = 2*(3^2)*(5^2)*11
Hence, 11 is the greatest prime factor
Statistics : Posted by kungfury42 • on 20 Oct 2022, 19:57 • Replies 332 • Views 2848
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