beater wrote:If positive integer x is a multiple of 6 and positive integer y is a multiple of 14, is xy a multiple of 105?
(1) x is a multiple of 9.
(2) y is a multiple of 25.
x = 2*3
y = 2*7
105 = 5*3*7
x*y = 2*3*2*7
Statement (1)
x = 3*3, we already know x = 2*3
x could be have 7 and 5 and cannot have 7 and 5. Insufficient.
Statement (2)
y= 5*5
for 105 we need 5*3*7. We already know, y=2*7, x = 2*3
x*y = 5*5*2*7*2*3
Sufficient.
Thus, B is the answer.
