MANRED wrote:

Why?????

If N is a positive integer, is the units digits of N iqual to 0 (zero)

1) 14 and 35 are factors of N

2) N=(2^5)*(3^2)*(5^7)*(7^6)

Answer: D

Yes or No question...

1. If 14 and 35 are factors of N, we know that 14 = 2*7 and 35 = 5*7. If you multiply 2*5*7 = unit digit is equal to 0. Yes...Suff...

2. Since we are only interested in the units digit only,

2^5 = some number with unit digit of 2

3^2= 9

5^7= some number with unit digit of 5

7^6= some number with unit digit of 9

so 2*9*9*5 = leads to unit digit of 0... Yes... Suff..

D