Question

The average of four numbers is 16. If three of them are 15, 18, and 20, find the fourth number.​

Answer 1

Answer:

Let the fourth number be x

so (15+18+20+x)/4=16

53+x/4=16

53 +x = 16*4

53 + x = 64

x = 64 - 53

x = 11 is the right answer.