Question

Find the sum of all even numbers between 1 to 150

Answer 1

The first and last even number between 1 and 150 are 2 and 148 respectively
a =2
d = 2 [we are dealing with even numbers only]
as per condition aₓ = 148
a+(x-1)d = 148
2+ 2(x-1)=148
2(1+x-1)=148
x=74
Sₓ = x/2{a+aₓ}
Sₓ =37(150)
Sₓ =5550