Question

Find the missing term.
625, 5, 125, 25, 25, ?, 5

Answer 1

take alternate numbers

625 ,125, 25, 5  here 5^4 , 5³,5², 5
next 
5, 25 , ? here 5, 5², 5³ = 125 

125 is correct answer

Answer 2

There are actually two series in the given series.Take the numbers alternately
One series --> 625 , 125 , 25, 5
Second series --> 5 , 25, ?

If we observe the 1st series --> 5⁴ , 5³ , 5² , 5¹
It is in decreasing order of power of 5

In 2nd series it is increasing orde rof power of 5
5¹, 5²,5³.........
So 5³ = 125

125 is the missing number.