Question

Average of first three numbers is twice the fourth number. If the average of all the four numbers is 28. Find the fourth number?

Answer 1

let the first number be X.

let the second number be y.

let the third number be z.

let the fourth number be w.

(x+y+z)/3= 2w

(x+y+z+w)/4= 28

x+y+z+w= 28*4

x+y+z+w= 112

x+y+z=112- w

(x+y+z)/3=2w

(112-w)/3=2w

112-w=3*2w

112- w=6w

112= 6w+ w

112= 7w

112/7=w

w=16

Answer = 16