A guy can walk a certain distance in 60 minutes. If he can run 3 times faster than he can walk, how much time must he run in order to cover the same distance in 50 minutes?
2006-12-31 03:18:15 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Let the distance be x
thus, speed of walking= x/60
speed of running= x/20
to cover the distance in time of 50 min, let him run for t min
thus,
(x/60)*(50-t)+(x/20)*(t)=x
solving this eqn. we get t= 5 min.
thus the man should run for 5 min.
2006-12-31 03:31:36 · answer #1 · answered by Riddhi 2 · 0⤊ 0⤋
We assume the distance is one unit. Therefore the walking speed is 1/60 unit per minute. The running speed will then be 3/60 unit per minute. In order to complete the unit distance in 50 minute, he has to run x minutes and walk 50-x minutes. The combined distance has to be 1 unit distance. The total distance becomes 3/60x+1/60(50-x)=1,
Solving for x, x=5. The guy has to run for 5 minutes and walk the rest of the way.
2006-12-31 11:37:48 · answer #2 · answered by cnt 2 · 0⤊ 0⤋
Eh...the last part "in 50 minutes" confuses me? You're looking for time right?
I'm going to ignore that part...
If he can walk a distance in 60 minutes, and he can run 3 times faster than he can walk, he can run the same distance in 60/3 = 20 minutes.
2006-12-31 11:23:39 · answer #3 · answered by Jim Burnell 6 · 0⤊ 0⤋
he must run 50 minutes to cover the same distance in 50 minutes.
2006-12-31 11:30:27 · answer #4 · answered by edgar 1 · 0⤊ 0⤋
He must 2.5 times the distance if he runs 3 times faster than he can walk
2006-12-31 11:32:02 · answer #5 · answered by Suhas 2 · 0⤊ 0⤋
To do ANYTHING in 50 minutes takes 50 minutes.
Jim is too kind, to a questioner who doesn't know what he's talking about.
Perhaps to cover the same distance in 50 minutes, he must run for 20 minutes and do something else for 30 minutes, such as take a nap.
2006-12-31 11:24:27 · answer #6 · answered by ? 6 · 1⤊ 1⤋
All formulas... sorry.
Distance (D) he can walk (w): D = 60 w
Running is 3 times walking speed: r = 3w
Here's the hard part, he's either walking or running in the 50 minutes... x = time running
r * x + w * (50 -x) = D
so, substituting:
3wx + 50w - wx = 60w
2wx = 10w
x = 5 minutes
2006-12-31 11:34:27 · answer #7 · answered by jm 1 · 0⤊ 0⤋
There's smth strange with your question: ...how much TIME must he run in order to cover the same distance in 50 MINUTES?
You ask for time and give time!
2006-12-31 11:22:55 · answer #8 · answered by t42 1 · 1⤊ 0⤋
Trick question.... you just said he has to run for 50 minutes....
2006-12-31 11:26:49 · answer #9 · answered by Amy 1 · 1⤊ 0⤋
This problem is in "Ask Marilyn" in the Parade Magazine section of today's Sunday newspaper.
2006-12-31 12:34:17 · answer #10 · answered by fcas80 7 · 0⤊ 0⤋