Bunuel wrote:
Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years ago?
A. 8
B. 18
C. 21
D. 26
E. 31
Brent is 18 years younger than Justin.
Let J = Justin's PRESET AGE
So, J-18 = Brent's PRESENT age
In 5 years, both people will be 5 years older
So, J + 5 = Justin's AGE IN 5 YEARS
And (J-18) + 5 = Brent's AGE IN 5 YEARS
Simplify to get: J - 13 = Brent's AGE IN 5 YEARS
In 5 years Brent will be half as old as Justin. In other words, IN 5 YEARS
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