Find the sum of all even natural numbers less than 75

Ans.

Range is 2, 74 and after every 1 number we will get an even number

This is an Arithmetic Progression where.

a= 2 ,d=2,l= 74

74=2+(n-1)*2
74=2+2*n-2
n=37

Required sum =

37/2*(2+74)
= 37*38
=1406