Average of 80 numbers are 42. When 5 more numbers are included, the average of 85 numbers become 45. Find the average of 5 numbers.

Solution(By Examveda Team)

Total of 80 numbers
= 80 × 42 = 3360
Now, total of 85 numbers
= 85 × 45 = 3825
Hence, sum of 5 numbers
= 3825 - 3360 = 465
Average of five numbers
= $$\frac{{465}}{5}$$ = 93

Alternatively,
Solve while reading method:
Average of 80 number was 42
When 5 more numbers are added average become 45
that means 3 is given to each number to make their average.
45 and 5 numbers also keep 45 as to maintain the entire average.
So, the sum of five numbers
= 240 + 225 = 465
Hence, average of five numbers = 93