Vincen wrote:By how many years is Jason older than Allison?
(1) Jason is 6 years older than twice David's age.
(2) In 8 years, Allison will be twice as old as David is now.
[spoiler]OA=C[/spoiler]
Source: Veritas Prep
Target question: By how many years is Jason older than Allison?
Statement 1: Jason is 6 years older than twice David's age.
Since we have no information about Allison, there was no way we can answer the
target question.
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: In 8 years, Allison will be twice as old as David is now.
Since we have no information about Jason, there was no way we can answer the
target question.
Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
Let J = Jason's PRESENT age
Let D = David's PRESENT age
Let A = Allison's PRESENT age
From statement 1, we can write:
J = 2D + 6
From statement 2, we can write:
A + 8 = 2D
Take the top equation and replace
2D with
A + 8 to get:
J = (A + 8 ) + 6
Simplify:
J = A + 14
This tells us that J is 14 greater than A
In other words,
Jason is 14 years older than Allison
Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C
Cheers,
Brent
