boomgoesthegmat wrote:Today Rebecca, who is 34 years old, and her daughter, who is 8 years old, celebrate their birthdays. How many years will pass before Rebecca's age is twice her daughter's age?
A) 10
B) 14
C) 18
D) 22
E) 26
Answer: C
I think the best (i.e., fastest) approach is to TEST the answer choices.
However, for those who prefer using algebra, here's an algebraic approach:
Let x be the number of years from today.
So, x years in the future, Rebecca's age will be 34 + x
And, x years in the future, her daughter's age will be 8 + x
We want Rebecca's future age to be twice her daughter's future age.
We can create the following "word equation": (Rebecca's future age) = 2(daughter's future age)
Or we can write: (34 + x) = 2(8 + x)
Expand to get: 34 + x = 16 + 2x
Solve to get: x = 18
Answer:
C
Cheers,
Brent
