Question 52

The average of 50 numbers is 75. If the average of first set of 25 numbers is 65, then what is the average of the second set of 25 numbers?

Solution

given average of 50 numbers is 75

$$\frac{sum\ of\ 50\ numbers}{50}$$=75

sum of 50 numbers=3750.

given that average of first 25 numbers is 65

$$\frac{sum\ of\ 25\ numbers}{25}$$=65

sum of 25 numbers =1625

to find the average of last 25 numbers subtract 1625 from 3750 and find average

i.e;

=>$$\frac{\left(3750-1625\right)}{25}$$

=>$$\frac{2125}{25}$$=85

hence answer is option C

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