BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Today, Anna is 10 years older than Michelle. If fifteen years ago, Anna was twice as old as Michelle, how old is Michell

Expert replies
by M7MBA » Wed Oct 07, 2020 10:01 am

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty

Today, Anna is 10 years older than Michelle. If fifteen years ago, Anna was twice as old as Michelle, how old is Michelle today?

a) 20
b) 22
c) 25
d) 28
e) 30

Answer: C

Source: Official Guide
Join the discussion
Source: — Problem Solving |

M7MBA wrote:
Wed Oct 07, 2020 10:01 am
Today, Anna is 10 years older than Michelle. If fifteen years ago, Anna was twice as old as Michelle, how old is Michelle today?

a) 20
b) 22
c) 25
d) 28
e) 30

Answer: C

Source: Official Guide
One option is to test the answer choices. In many cases, it can be the fastest approach.

A) 20
If Michelle is 20 years old TODAY, then Anna is 30 years old TODAY (since she's 10 years older than Michelle)
So, 15 YEARS AGO, Michelle was 5 years old and Anna was 15 years old
This does NOT meet the given condition that Anna was twice as old as Michelle 15 YEARS AGO
Eliminate A

B) 22
If Michelle is 22 years old TODAY, then Anna is 32 years old TODAY (since she's 10 years older than Michelle)
So, 15 YEARS AGO, Michelle was 7 years old and Anna was 17 years old
This does NOT meet the given condition that Anna was twice as old as Michelle 15 YEARS AGO
Eliminate B

C) 25
If Michelle is 25 years old TODAY, then Anna is 35 years old TODAY (since she's 10 years older than Michelle)
So, 15 YEARS AGO, Michelle was 10 years old and Anna was 20 years old
This DOES meet the given condition that Anna was twice as old as Michelle 15 YEARS AGO

Answer: C
Brent Hanneson - Creator of GMATPrepNow.com
Image
Join the discussion

M7MBA wrote:
Wed Oct 07, 2020 10:01 am
Today, Anna is 10 years older than Michelle. If fifteen years ago, Anna was twice as old as Michelle, how old is Michelle today?

a) 20
b) 22
c) 25
d) 28
e) 30

Answer: C

Source: Official Guide
Solution:

We can let A = Anna’s current age and M = Michelle’s current age. We can create the equations:

A = M + 10

and

A - 15 = 2(M - 15)

Substituting M + 10 for A in the second equation, we have:

M + 10 - 15 = 2(M - 15)

M - 5 = 2M - 30

25 = M

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Join the discussion