pzazz12 wrote:Three friends-whose walking rates are 1 ft./sec., 3ft./sec.,and 6ft./sec. start together walking in the same direction around a circular track that is 300 feet in circumference.After how many minutes are the three of them together again?
A. 5 mins
B. 10 mins
C. 15 mins
D. 3 mins
E. 7 mins
help me to solve it......
Rates per minute for the 3 friends:
60*1 = 60ft/min
60*3 = 180ft/min
60*6 = 360ft/min.
Now we can plug in the answers, which represent the time spent traveling around the track. We should start with the smallest answer choice.
Answer choice D:
60*3 = 180 ft.
180*3 = 540 feet = 1 lap + 240 ft.
Doesn't work.
Answer choice A:
60*5 = 300 ft = 1 lap
180*5 = 900 ft. = 3 laps
360*5 = 1800 ft. = 6 laps
Success!
The correct answer is A.
I think that plugging in the answers is just as quick as -- if not quicker than -- coming up with an equation that we would then have to solve.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
