Question

The mean of five numbers is 10. if one is included the mean of the remaining numbers becomes 9. find the value of the included number.​

Answer 1

Answer:   4

Step-by-step explanation:

Mean of 5 nos. = 10

∴ Sum of the 5 nos. = 10 × 5 = 50

Let the included num be x.

∴ Mean of the nos. = $\frac{50+x}{6}$

⇒  $\frac{50+x}{6}$  = 9

⇒ 50 + x = 9 × 6

⇒ x = 54 - 50

⇒ x = 4

∴ The included number is 4.

Hope it helps. Thanks!!