The average of 16 numbers is 23. The average of the first 7 numbers is 21 and that of the last 8 numbers is 24. Find the 8th number.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 29.
We know that,
Average = Sum of observations/Number of observations
According to the given question,
Sum of 16 numbers = 23 × 16 = 368
Sum of first 7 numbers = 21 × 7 = 147
Sum of last 8 numbers = 24 × 8 = 192
Now, the sum of the first 7 and last 8 numbers = 147 + 192 = 339
Now,
8th number is = 368 - 339 = 29