Source: Veritas Prep
A frog is climbing a greasy pole. The frog can climb 2 centimeters every half-hour and it takes a break to rest for half an hour after every 2 hours, during which it slips by 1 centimeter. How much time it will take to climb a 28-centimeter pole?
A. 7.5 hours
B. 8.5 hours
C. 9.25 hours
D. 9.75 hours
E. 10 hours
The OA is C.
A frog is climbing a greasy pole. The frog can climb 2
This topic has expert replies
-
- Moderator
- Posts: 2205
- Joined: Sun Oct 15, 2017 1:50 pm
- Followed by:6 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
GMAT/MBA Expert
- Brent@GMATPrepNow
- 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
Let's solve this by making tableBTGmoderatorLU wrote:Source: Veritas Prep
A frog is climbing a greasy pole. The frog can climb 2 centimeters every half-hour and it takes a break to rest for half an hour after every 2 hours, during which it slips by 1 centimeter. How much time it will take to climb a 28-centimeter pole?
A. 7.5 hours
B. 8.5 hours
C. 9.25 hours
D. 9.75 hours
E. 10 hours
Time elapsed | height
1 hours | 4 cm
2 hours | 8 cm
REST (slide)
2.5 hours | 7 cm
3.5 hours | 11 cm
4.5 hours | 15 cm
REST (slide)
5 hours | 14 cm
6 hours | 18 cm
7 hours | 22 cm
REST (slide)
7.5 hours | 21 cm
8.5 hours | 25 cm
9.5 hours | 29 cm
Oops - we want too far.
We can see that the frog reaches a height of 28 cm BETWEEN 8.5 hours and 9.5 hours.
So, the correct answer must be C
Cheers,
Brent
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7222
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
In 2.5 hours, the frog can climb a total of 8 centimeters but will slip back 1 centimeter; thus, it will have covered a distance of 7 centimeters. We need to be careful not to just conclude that it will take 2.5 x 4 = 10 hours, because once the frog reaches the top, it will not rest and slip back again. Instead, we proceed as follows:BTGmoderatorLU wrote:Source: Veritas Prep
A frog is climbing a greasy pole. The frog can climb 2 centimeters every half-hour and it takes a break to rest for half an hour after every 2 hours, during which it slips by 1 centimeter. How much time it will take to climb a 28-centimeter pole?
A. 7.5 hours
B. 8.5 hours
C. 9.25 hours
D. 9.75 hours
E. 10 hours
The OA is C.
In 7.5 hours, the frog will be 21 centimeters high.
In 8 hours, the frog will be at 23 centimeters.
In 8.5 hours, the frog will be at 25 centimeters.
In 9 hours, the frog will be at 27 centimeters.
Since it takes 0.5 hours to climb 2 centimeters, it will take 0.25 hours to climb the final centimeter, and thus the frog will be on the top of the 28-centimeter pole in 9 + 0.25 = 9.25 hours.
Answer: C
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews