Please solve this

Asked by aastharoy997 | 14th May, 2020, 10:08: AM

Expert Answer:

Question: The average of 25 observations is 80 and the average of another 55 observations is 65. Find the approximate average of all these observations.
Solution: 
Let the sum of 25 observations be a.
As the average is 80, we have
a = 25 x 80 = 2000
Let the sum of next 55 observations be b. 
As the average is 65, we have
b = 55 x 65 = 3575
The total number of observations is 25+55=80.
Sum of all the observations is a+b=2000+3575
Average of these 80 observations is = 5575/80 = 69.68 = 70 (approximately)
Approximate average of all these observations is 70.

Answered by Renu Varma | 14th May, 2020, 11:58: AM