Question

The mean of 18,24,15,2x+1 and 12 is 21. find the value of x ​

Answer 1

Answer:

$mean = \frac{18 + 24 + 15 + 2x + 1 + 12}{5} \\ 21= \frac{18 + 24 + 15 + 2x + 1 + 12}{5} \\ 21 = \frac{70 + 2x}{5} \\ 21 \times 5 = 70 + 2x \\ 105 = 70 + 2x \\ 105 - 70 = 2x \\ 35 = 2x \\ \implies \: x = \frac{35}{2} \\ \implies \: x = 17.5$