Answers

2016-03-03T14:57:04+05:30
52 years.
two years ago the mean age for 40 ppl was 11 yrs. So total age two years ago should be 11 x 40 = 440 .

Now, after two years the total age should go up 2 times 40 people = 80 + 440 = 520.

When one person left, the for 39 ppl the mean age is 12. That is 12 times 39 = 468.

Deduct 520 - 468 = 52 years is the age of the person left.
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