Question 93605
This is an AP.
The n-th term of an AP with first term 'a' and common difference 'd' is 
{{{t[n]=a+(n-1)d}}}


Here, a = 25 and d = -15. 
So the 100-th term is
{{{t[100]=25-(100-1)15}}}
{{{t[100]=25-1500+15}}}
{{{t[100]=-1460}}}