Question 988859
The series here is 25+26+27+...41
Since the given series is in arithmetic 
Progression we need to first find n
Either using n2-n1+1 i.e(41-25+1)=17 or
Using the formula n2=n1+(n-1)d where d is
The distance between the consecutive numbers 
I.e 1..using this u get n=17

Now using the formula sum=(n/2)(n1+(n-1)d)
We get the value as 561