Question

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

Answer 1

Mean of given data =`(18 + 24 + 15 + 2x + 1 + 12)/(5)`

⇒ 21 = `(70 + 2x) / (5)`

⇒ 5 x 21 = 70 + 2x

⇒15 = 70 + 2x

⇒ 2x = 105 - 70

⇒ 2x = 35

⇒ x = `35/2`

⇒ x = 17.5