Answer: 16 years old
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Work Shown:
x = his age now
x+11 = his age 11 years into the future
x-7 = his age 7 years ago
The equation to set up is
x+11 = 3(x-7)
since his age 11 years into the future is triple that of his age 7 years ago.
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Let's solve for x.
x+11 = 3(x-7)
x+11 = 3x-21
x-3x = -21-11
-2x = -32
x = -32/(-2)
x = 16
He is currently 16 years old.
11 years from now he'll be 16+11 = 27, and 7 years ago he was 16-7 = 9.
Note that 9*3 = 27 to help confirm the answer.