Question

Find the mean of 25 given numbers when the mean of 10 of them is 13 and the mean of the remaining numbers is 18.

Answer 1

Mean of first 10 numbers = 13

Sum of first 10 numbers = 10×13 = 130

Total numbers = 25

Remaining = 25 - 10 = 15

Mean of the remaining 15 numbers = 18

Sum of remaining numbers = 15×18 = 270

Total sum = 130 + 270

= 400

Sum of 25 numbers = 400

Mean = 400÷ 25

= 16

Hope this will help...

Answer 2

Answer:

The answer is 16

Step-by-step explanation:

If the mean of 10 observations is 13 , then the sum of 10 observations is 130 [ 13x10=130]--->(1)

If the mean of the other 15 observations is 18 , then the sum of 15 observations is 270 [ 18x15=270]--->(2)

From equations (1) and (2),

The sum of 25 observations = 130+270

                                                = 400

Then the mean of 25 observations = 400/25

                                                          = 16