Question

The mean of 5 numbers is 18. If one number is excluded, their mean is 16. Find the excluded number.

Answer 1

Answer:

Let the sum of the numbers be x and the excluded number be n.

x/5=18

x=90

(90-n)/4=16

90-n=64

n=26

PLS MARK IT BRAINLIEST!

Answer 2

Answer:

$\\ \: \: \: \sf \: Here, \: \: \: n = 5, \: \: \bar{x} = 18. \\ \\ \\ \therefore \sf \bar x = \frac{1}{n} \: \bigg ( \: \sum \: x_i \bigg) \\ \\ \\ \implies \sf \sum \: x_i = n \: \bar{x} \\ \\ \\ \implies \sf \sum \: x_i = 5 \times 18 = 90.$

• So, total of 5 numbers = 90.
• Let the excluded number be a, Then, total of 4 numbers is 90 - a.

$\\ \therefore \sf \: Mean \: of \: 4 \: numbers = \frac{90 - a}{4} \\ \\ \\ \implies \sf16 = \frac{90 - a}{4} \\ \\ \\ \implies \sf90 - a = 64 \\ \\ \\ \implies \sf \blue{a = 26}$

Hence, the excluded number is 26.