CMAT 2015 Solved Question Paper

Question : 24 of 100

Marks: +1, -0

The average age of a group of workers is 42 yr. If eight new workers of average age 36 yr join the group, the average age of the group becomes 40 yr. How many workers were there in the group initially?

Validate

Solution:

(d) Let these is x workers present initially.
Average age of x workers = 42 yr
Total age of x workers =42x yr
Average age of 8 new workers = 36 yr
Total age of 8 new workers = 36 x 8 = 288 yr
Now, according to the question,

{42x + 288}/{x+8}

= 40
⇒42x + 288 = 40(x+ 8)
⇒ 42x - 40x = 40 x 8 -288
⇒ 2x = 32
∴ x =

32/2

= 16
Hence, initially these are 16 workers.

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