Question

consider the numbers 25n and where n is a natural number check whether there is any value of n for which 25n ends with digit 0

Answer 1

heya
Factors of 25 are 5*5
so 25^n can never end with 0 as all the numbers ending with 0 have both 2 and 5 as it's factors but 25 doesn't have 2 as a factor but only 5

Answer 2

the natural numbers are 1,2,3........25n
tn=a+(n-1)d
tn=1+25n-1
tn=25n
for condition that getting zero
put n=0
we get tn=0