The average of $10$ numbers is $15$ and that of $15$ numbers is $20$. The average of all $25$ numbers is:
Practice this question from Chapter Mock 6: Average and Ages, with options and an explanation.
Question
The average of $10$ numbers is $15$ and that of $15$ numbers is $20$. The average of all $25$ numbers is:
Option A
17
Option B — Correct answer
18
Correct choice.
Option C
19
Option D
20
Explanation
Combined average $=\frac{10\times15+15\times20}{25}=\frac{450}{25}=18$.