The average of 9 consecutive numbers is 20. The smallest of these numbers is :
Answer & explanation
Correct answer: option 3
Let the smallest number of the series be x
x + (x + 1) + .....+ (x + 7) + (x + 8) = 20 x 9
⇒ 9x + ( 1 + 2 + ....+ 7 + 8) = 180
⇒ 9x + 36 = 180
⇒ x = \(\frac{180 - 36}{9}\)
⇒ x = 16
∴ The smallest of these numbers is 16