If any one person can complete a given task in 2 hours, how many peopl

Question

If any one person can complete a given task in 2 hours, how many people should be hired to complete the task in 10 minutes?

A. 5
B. 6
C. 12 
D. 20 
E. 120

unpa0814 · Answer

I get A as an OA. Can anyone confirm please, I tend to struggle with rate questions.
Amount=Rate*Time
1=Rate*2---Rate=1/2
so 1/2*10=5, hence 5 people should be hired

rohit8865 · Answer

Hi unpa0814

Ans should be 12 ....

1*2 = No. of persons *10/60 (since 10 minutes = 10/60 hrs)

thus no. of persons = 60*2/10 =12

Ans C

rohit8865 · Answer

unpa0814

Better if u understand this way

rate of person is 1/2 ,it means that man does 1/2 work in 1 hrs

let N be the no. of persons then thier rate will be N/2 
and the time they will finsh =10 minutes or their rate should be 1/10 or 60/10 (since 10minutes =10/60 hrs)

thus N/2 = 60/10
N=12

Ans C

gvvsnraju@1 · Answer

1 persons - 2 Hours - Task
1 p - 1 H - T/2
1 p - 10X6 min - T/2
1p - 10 min - T/12
12p - 10 min - T

So, 12 persons should be hired to complete the given task in 10 min. C

Regards
Narayana Raju

joondez · Answer

I found this to be really tricky. I got it wrong at first because I didn't convert minutes and hours.

It takes 1 person to finish one task in 2 hours. Convert this to 2*60 = 120 minutes.
How many people to finish the same task in ten minutes?

Well, if it takes 1 person 120 minutes to finish the task, then in ten minutes they will finish 10/120 = 1/12 of the task.
If one person can finish 1/12 in ten minutes, then it will take 12 people to finish 12/12. So the answer is C, 12 people.

matthewsmith_89 · Answer

work = rate x time
120 = 1 x 120

work = rate x time
120 = r x 10
r = 12

Therefore, the answer is C

KrishnakumarKA1 · Answer

rate of the person = 1/2 per hr or 1/120 per minute
rate of n person = n/120

n/120 . 10 = 1
n = 12

SI777 · Answer

m1*h1 = m2 * h2

1 * 120 = x * 10

x=12 Ans C

ScottTargetTestPrep · Answer

We are given that the rate of 1 person to complete a task is 1/2. We need to determine how many people are needed to complete the task in 10 minutes or 1/6 of an hour. If we let n = the number of people needed, then n x (1/2) = n/2 is the rate of these n people. We can now create the following equation:

rate x time = work

n/2 x 1/6 = 1

n/12 = 1

n = 12

Answer: C

sindropsilence · Answer

Generalise understanding
 
Our objective is to generalise our understanding as much as we can, so we deal with one concept that can be applied to multiple situations with a slight change in terminology. This problem is of the type x people/machines work for y hours to do certain work. That x could be typists, painters, tree planters, machines, labourers, etc.

Approach

When 6 people/machines work for 4 hours, visualise it in your mind. 6 people sewing clothes for 4 hours. 6 painters painting a house for 4 hours. 6 machines running in a factory and producing biscuits. Now what does that mean? Simplify further. 6 people sewing clothes for 4 hours means each of them has worked for 4 hours, since they all were sitting in the factory and working for the entire 4 hours. So the total number of hours of work done is 6 x 4 = 24 hours of work done. Pause for a while. Understand what this means. This means that we got 24 hours of work done. So now we can express work done not in terms of number of shirts produced but in terms of no of hours. So if we had to get 48 hours worth of work done, those 6 people would have to sit for twice the amount of time - 8 hours, which is 48/6. Generalise this in your mind. I first need to know the total amount of work that needs to be done in terms of hours, and then divide that by the number of people who are working.

In the present case, 1 person completed the task in 2 hours, so the work done was worth 2 hours. If we need to find the number of people required to do the same work in 10 mins, we ask how much was that work worth in minutes? It was 2 hours, hence 120 mins worth of work. Now 120 mins worth of work was done by 1 person, and if we need that same work done in 10 mins, we would need 120/10 = 12 people. Each of these 12 people would work for 10 minutes each, which would add up to 120 mins.

Conclusion

When x people/machines work together for y hours, each of them works for y hours each, so the total work done is worth xy hours. If the no. of people/machines increase, the same work would need less time to complete, since everyone is working at the same efficiency or rate. If you need to get the same work done faster, you would need more people.

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