Brent@GMATPrepNow wrote:Ann and Bea leave Townville at the same time and travel towards Villageton, which is 2K kilometers away. Their individual speeds are constant, but Ann's speed is four times Bea's speed. Upon reaching Villageton, Ann immediately turns around and drives toward Townville until she meets Bea. When they meet, how many kilometers has Bea traveled?
A) K/5
B) K/4
C) 2K/3
D) 3K/4
E) 4K/5
Answer:
E
Source:
www.gmatprepnow.com
Difficulty level: 700
David has nicely demonstrated the input-output approach for this question.
Here's an algebraic solution:
Let B = the distance Bea traveled
Let R = Bea's speed.
NOTE: the total distance from Townville to Villageton and then BACK TO Townville = 4K.
So, 4K - B = the distance Ann traveled
And 4R = Ann's speed (since her speed is 4 times Bea's speed)
From here, let's create a WORD EQUATION that uses distance and speed.
How about:
Ann's travel time =
Bea's travel time
Time = distance/rate, so we get:
(4K - B)/4R =
B/R
Cross multiply to get: (B)(4R) = (R)(4K - B)
Expand: 4BR = 4RK - BR
Add BR to both sides: 5BR = 4RK
Divide both sides by R to get: 5B = 4K
Divide both sides by 5 to get: B = 4K/5
Answer:
E
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
