Question

Solve this problem of reasoning 3:78::5:?

Answer 1

we know that 
product of extreme = product of mean
3*?=78*5
the answer will be 78*5/3=130

Answer 2

The next number will be 130 because we can see that 3 multiplied by 26 is 78, in the same way, 5 will be with 130.