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

Redeem

Automobile A is traveling at two-thirds the speed that Automobile B is traveling. How fast is Automobile A traveling?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 1223
Joined: Sat Feb 15, 2020 2:23 pm
Followed by:1 members

Automobile A is traveling at two-thirds the speed that Automobile B is traveling. How fast is Automobile A traveling?

by BTGModeratorVI » Sun Jul 19, 2020 1:49 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Automobile A is traveling at two-thirds the speed that Automobile B is traveling. How fast is Automobile A traveling?

(1) If both automobiles increased their speed by 10 miles per hour, Automobile A would be traveling at three-quarters the speed that Automobile B would be traveling.

(2) If both automobiles decreased their speed by 10 miles per hour, Automobile A would be traveling at half the speed that Automobile B would be traveling

Answer: D
Source: Princeton Review
Top
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

Re: Automobile A is traveling at two-thirds the speed that Automobile B is traveling. How fast is Automobile A traveling

by Brent@GMATPrepNow » Tue Jul 21, 2020 7:49 am
BTGModeratorVI wrote: ↑
Sun Jul 19, 2020 1:49 pm
 Automobile A is traveling at two-thirds the speed that Automobile B is traveling. How fast is Automobile A traveling?

(1) If both automobiles increased their speed by 10 miles per hour, Automobile A would be traveling at three-quarters the speed that Automobile B would be traveling.

(2) If both automobiles decreased their speed by 10 miles per hour, Automobile A would be traveling at half the speed that Automobile B would be traveling

Answer: D
Source: Princeton Review
Given: Automobile A is traveling at two-thirds the speed that Automobile B is traveling.
Let A = Car A's speed
Let B = Car B's speed
So, we can write: A = (2/3)B

Target question: What is the value of A?

Statement 1: If both automobiles increased their speed by 10 miles per hour, Automobile A would be traveling at three-quarters the speed that Automobile B would be traveling.
Car A's new speed = A + 10
Car B's new speed = B + 10
So, we can write: A + 10 = (3/4)(B + 10)
We already know that: A = (2/3)B
IMPORTANT: Since we have a system of 2 different linear equations with 2 variables, we COULD solve the system for A and B (but we'd never waste valuable time on test day doing so)
So, we COULD answer the target question with certainty.
Statement 1 is SUFFICIENT

Statement 2: If both automobiles decreased their speed by 10 miles per hour, Automobile A would be traveling at half the speed that Automobile B would be traveling
Car A's new speed = A - 10
Car B's new speed = B - 10
So, we can write: A - 10 = (1/2)(B - 10)
We already know that: A = (2/3)B
Once again, we have a system of 2 different linear equations with 2 variables, which we COULD solve for A and B.
Statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1