1*3*5=15 ;
Now if we multiply any odd no. With a no. ending with 5 then we found also a new no. ending with 5.
Hence, the no. of zeroes at the right end of the product is zero.

This is appeared to be a series of odd numbers. So there must not be any term like '10','20'. Above all, we know that the fundamental criteria to have a zero in a product is to have a pair of (2,5) as the product of 2 and 5 is 10. This gives a '0' . But In the above question there is even term. So there is not any '2'(an even number). So the pair of (2,5) can't be formed. That's why the answer is 0 i.e., the number of zeros at the right end of the product is 0.