.
the sum of three consecutive 
numbers is 42. What are the numbers?
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Answer. The three consecutive integer numbers are 13, 14 and 15.
Solution
Let x be the middle of the three consecutive numbers.
Then the lesser of the three is (x-1), and
the greater of the three is (x+1).
So, our numbers are (x-1), x, and (x+1).
Their sum is
(x-1) + x + (x+1) = 3x,
and it is equal 42:
3x = 42.
Hence, x = 
= 14, and the three numbers are 13, 14 and 15.
