Total work = 5000 man daysgmatmachoman wrote:50 persons can complete the work in 100 days. In how many days will the work be completed if 10 persons start the work and 10 person join after every 10 days?
thanks .I made a mistake in calculation.edited it now.ajith wrote:Total work = 5000 man daysgmatmachoman wrote:50 persons can complete the work in 100 days. In how many days will the work be completed if 10 persons start the work and 10 person join after every 10 days?
Total work done in first 10 days = 100 man days
Total work done in second 10 days = 200 man days
Total work done in nth 10 days = n*100 mandays
sum = n(n+1)*50
now n(n+1)*50> 5000
n(n+1)> 100
n>10
till 10th 10 days work worth 4500 man days would be done
We have 110 people to finish remaining 500
who will finish it in 500/110 days
total days = 100 + 50/11
in one day, 50 persons complete 1% of the work and a single person completes 1/50 % OR .02% of the work.gmatmachoman wrote:50 persons can complete the work in 100 days. In how many days will the work be completed if 10 persons start the work and 10 person join after every 10 days?
"till 10th 10 days" means 90 days are over. So, while calculating the total days in the end it should be 90+ something.ajith wrote:till 10th 10 days work worth 4500 man days would be done
We have 110 people to finish remaining 500
who will finish it in 500/110 days
total days = 100 + 50/11
yes, you're correct. To solve this question, assumptions should be made. But, all these are assumptions,sk818020 wrote:Is this the entire question?
The only reason I ask is because you couldn't really give an solid answer as the question is written. In the solutions above there is an assumption that all the workers are working at an equal and constant rate. The question does not tell us to make this assumption.
The reason this is an issue is what if 20% of the workers did 80% of the total work (some workers more efficient than others)? It would then be very relavent to know when those workers were added. More importantly you need to know the rate at which each individual worker worked to answer this questions with any certaintly, if the question does not state that all workers work at and equal and constant rate.
Thanks,
Jared
Well, generally speaking, all the questions are hypotheticals, but I've never seen a quant GMAT question where you had to make any further assumptions to get the answer. All the information you need should be in the question stem. I getting at that typically you won't see a question like this on the GMAT.harshavardhanc wrote:yes, you're correct. To solve this question, assumptions should be made. But, all these are assumptions,sk818020 wrote:Is this the entire question?
The only reason I ask is because you couldn't really give an solid answer as the question is written. In the solutions above there is an assumption that all the workers are working at an equal and constant rate. The question does not tell us to make this assumption.
The reason this is an issue is what if 20% of the workers did 80% of the total work (some workers more efficient than others)? It would then be very relavent to know when those workers were added. More importantly you need to know the rate at which each individual worker worked to answer this questions with any certaintly, if the question does not state that all workers work at and equal and constant rate.
Thanks,
Jared
are given as facts in the question itself which in normal cases. So, it doesn't hurt to assume general working efficiencies as same and start working on the numbers.
However, there is a BIG assumption that the workers can be more than 50. The first sentence says the work can be done by 50 workers in 100 days. So, someone might think that is the total number of persons who can work on the job. Answer in that case would be different.
