Question

Find three consecutive even numbers such that the sum of the first and the third is 40

Answer 1

let the even no. be x,x+2,x+4
x+x+4=40
2x+4=40
2x=36
x=18
x+4=18+4=22

Answer 2

three consecutive even numbers are 2x, 2x+2, 2x+4

x can be even or odd number but 2x will be even number

sum of the first and the third is 40
so, 2x + 2x + 4 = 40
4x + 4 = 40
4x = 40 - 4
4x = 36
x = 36/4
x = 9

so three consecutive numbers are
2x = 2*9 = 18
2x +2 = (2*9)+2 = 18+2 = 20
2x + 4 = (2*9) + 4 = 18+4 = 22

18, 20, 22 are three consecutive numbers