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 $=\frac{465}{5}=93$

Alternate Solution:

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