If Sam were twice as old as he is, he would be 40 years

[swerve]

If Sam were twice as old as he is, he would be 40 years older than Jim. If Jim is 10 years younger than Sam, how old is Sam?

A. 20
B. 30
C. 40
D. 50
E. 60

The OA is B

Source: Official Guide

[Brent@GMATPrepNow]

If Sam were twice as old as he is, he would be 40 years older than Jim. If Jim is 10 years younger than Sam, how old is Sam?

A. 20
B. 30
C. 40
D. 50
E. 60

Jim is 10 years younger than Sam
Let x = Sam's PRESENT age
So, x - 10 = Jim's PRESENT age

If Sam were twice as old as he is, he would be 40 years older than Jim.
TWICE Sam's age = 2x
So, we can write: 2x = (x - 10) + 40
Simplify: 2x = x + 30
Solve: x = 30

Answer: B

Cheers,
Brent

[[email protected]]

Hi All,

We're told that if Sam were TWICE as old as he is, then he would be 40 years older than Jim and that Jim is currently 10 years YOUNGER than Sam. We're asked for Sam's current age. This question can be solved in a couple of different ways, including by TESTing THE ANSWERS. Since the difference between the two ages is currently 10 years, and the answer choices are in increasing increments of 10 years, it's likely that we're dealing with one of the smaller answers (since by DOUBLING Sam's age will only increase the difference to 40 years). Let's TEST Answer B first:

Answer B: 30 years

IF... Sam is 30 years old
Jim is 30 - 10 = 20 years old
Doubling Sam's age.... (2)(30) = 60 years
60 - 20 = 40 years difference.
This matches everything that we were told, so this must be the answer.

Final Answer: B

GMAT assassins aren't born, they're made,
Rich

[Scott@TargetTestPrep]

If Sam were twice as old as he is, he would be 40 years older than Jim. If Jim is 10 years younger than Sam, how old is Sam?

A. 20
B. 30
C. 40
D. 50
E. 60

The OA is B

Source: Official Guide

We can let the current ages of Sam and Jim be S and J, respectively, and create the equations:

2S = J + 40

and

J = S - 10

Substituting, we have:

2S = S - 10 + 40

S = 30

Answer: B