Answer:

28

Step-by-step explanation:

The mean of fifteen numbers is 30 and the mean of ten numbers is 25. What is the mean of all the twenty-five numbers?

Given: mean of 15 no. = 30

           mean of 10 no. = 25

Required: mean of all 25 no.

Solution:

Get the sum of 15 numbers and the sum of 10 numbers:

sum of 15 numbers  = 30 × 15 = 450

sum of 10 numbers = 25  × 10 = 250

Add the sum of 15 numbers and sum of 10 numbers to get the total sum of all 25 numbers:

Total = 450 +250 = 700

Get the mean of all 25 numbers by dividing the total by 25:

mean of 25 numbers = 700 ÷ 25 = 28

Verified answer

Answer: 28

Step-by-step explanation:

15numbers * 30 = 450

10numbers * 25 =250

> 450 + 250 = 700

> 15numbers + 10 numbers = 25

> 700 / 25 = 28