Question

Find the sum of even positive integers between 1 and 200.

Answer 1

even number between 1 and 200 are2
2,4,6,.......200
first find no of term
tn=a+(n-1) d
200=2+(n-1) 2
198/2=n-1
n=50
now use sum of AP formula
Sn=n/2 {2a+(n-1) d}
=50/2 {2 x 2+(50-1) x 2}=25 x 102
=2550