Question

If the average of x and y is 11 and the average of x, y and z is 5, what is the value of z? ​

Answer 1

z = -17

Explanation:

If the average of x and y is 11, then;

x+y/2 = 11

x+y = 2 + 11

x+y = 22 .... 1

similarly, if average of x, y and z is 5, then;

x+y+z/3 = 5

x+y+z = 3*5

x+y+z = 15

Since x+y = 22

22 + z = 5

z = 5 - 22

z = -17

Hence the value of z is -17