Question

average of 7 ,
9, 11, x, 17, 18 is 12.5 the value of x will be​

Answer 1

Average= sum of observation/number of observations

$12.5 = \frac{9 + 11 + x + 17 + 18}{5} \\ 62.5 = x + 55 \\ 62.5 - 55 = x = 7.5$

Answer 2

Hey mate here is your answer ❤️...