Last year Harolds average time to finish the qualifying even

Question

Last year Harolds average time to finish the qualifying event was three hours. If he knows that he can increase his speed this year by 20%, how many minutes should it take him to complete the event?

(A) 150
 (B) 144
 (C) 120
 (D) 90
 (E) 36

whiplash2411 · Accepted Answer

So we know that Rate  = \frac{A}{T}  where A represents either a distance or a job or whatever. Let's assume that the qualifying event = A, here.

In the first year, we have Rate  = \frac{A}{3*60} = \frac{A}{180}  per minute. He increases this speed by 20%, which means that new rate  = \frac{120}{100}*\frac{A}{180} = \frac{A}{150}

From this you can see that the new time is 150 minutes.

cleetus · Answer

Time taken to complete the work = 3hrs
Let the total work be 300 (assumed value. Its always better if u assume good values if the question consists of percentage or percentage incease)
so the speed = 300/3 = 100

Now the speed is increased by 20%. so the new speed = 120 and the total work is still the same = 300.
There for the new time taken to complete the event = 300/120 = 5/2 hrs. = 2hrs 30 mins = 150 mins
Answer A

Bunuel · Answer

Time, rate and job in work problems are in the same relationship as time, speed (rate) and distance in rate problems. time*speed=distance <--> time*rate=job \ done . So if the rate is 1.2 times more then the time needed to complete the same job will be 1.2 times less: he needs 180 minutes with original rate to do the job --> he'll need 180/1.2=150 minutes to complete the same jon with the rate increased 1.2 times. Answer: A. Check this for more on work problem: word-translations-rates-work-104208.html?hilit=relationship%20rate#p812628 Hope it helps.

KarishmaB · Answer

Think in terms of ratios, if you will...

For same distance/work, 
Old Speed : New Speed = 5 : 6 (An increase of 20%)
So Old Time : New Time = 6 : 5 = 3 hrs: 2.5 hrs
(The ratio will be inverse if work is same because Work = Rate * Time)
New Time = 2.5*60 = 150 minutes

TGC · Answer

Simple And sober approach:

We know that , Rate * Time = Work, now work being constant we can write.

Time = Work/Rate

Instance 1: 3=w/r

Instance 2: t=w/1.2r

Dividing 1/2 => t=2.5 hours = 150 minutes

Rgds,
TGC!

reto · Answer

Rate * Time = Job Done
1/180 * 180 = 1
1/144 * 144 = 1 (New Rate is 20% faster, hence 180 - 0.2*180 = 144 (NOT 150)). What's wrong with that? I see that the difference here is, you divide 180 by 1.2 - but i don't get it why "20% faster" is 180/1.2 instead of 180 - 0.2*180 ...

Please help

Thank you very much

Answer: A.

gracie · Answer

if his speed increases by 6/5, 
his time will decrease by 5/6
5/6*180=150 minutes

hsbinfy · Answer

rate increase >time will be less, or
rate decrease>more time

here the rate increased 1.2 times..so time to finish the event will be less than 180 minutes =180/1.2=150 min

deepthit · Answer

x(3) = 3x ->>> equ 1 
1.20x (time) = 3x

time = 3x/1.2x *(60) because question is asking about minutes

time = 3*50 = 150 minutes

rohit8865 · Answer

work completed in 3hr
it means rate or speed =1/3
rate after increase of 20% =1/3*6/5 = 2/5
thus time needed =5/2 =2.5 hrs =150mnts

Ans A

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Last year Harolds average time to finish the qualifying even

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