Home » Aptitude » Time and Work

A group of men can complete a job in K hours. After every 4 hours, half the number of men working at that point of time leave the job. Continuing this way if the job is finished in 16 hours, what is the value of K ?

7 hrs
7.5 hrs
8 hrs
8.25 hrs

Correct Answer: 7.5 hrs

Explanation:

Let there are L men

job requires LK man hours.

job completed in first 4 hrs = L x 4 = 4L

job completed in next 4 hrs = 4 x L/2 = 2L

job completed in next 4 hrs = 4 x L/4 = L

job completed in last 4 hrs = 4 x L/8 = L/2

4L + 2L + L + L/2 = KL

K = 7+1/2 = 7.5 hours.

← Previous Question Next Question→

More Questions from Time and Work

P and Q were assigned to do a work for an amount of 1200. P alone can do it in 15 days while Q can do it in 12 days. With the help of R they finish the work in 6 days. Find the share of R ?
If 5 men and 2 boys working together, can do four times as much work per hour as a man and a boy together. Find the ratio of the work done by a man and that of a boy for a given time ?
45 men working 9 hours per day dig 40 m deep. How many extra men should be put to dig to a depth of 56 m working 7 hours per day ?
If 34 men completed 2/5th of a work in 8 days working 9 hours a day. How many more man should be engaged to finish the rest of the work in 6 days working 9 hours a day ?
P alone can complete a piece of work in 6 days. Work done by Q alone in one day is equal to one-third of the work done by P alone in one day. In how many days can the work be completed if P and Q work together ?
S, T and U together can complete a work in 30 days. If the ratio of efficiency of S, T and U is 20 : 15 : 12 respectively, then in how many days U alone can complete the same work?
A and B together finish a wor in 20 days.They worked together for 15 days and then B left. Afer another 10 days,A finished the remaining work. In how many days A alone can finish the job?
Ten women can do a work in six days. Six men can complete the same work in five days. What is the ratio between the capacity of a man and a woman?
A shopkeeper has a job to print certain number of documents and there are three machines P, Q and R for this job. P can complete the job in 3 days, Q can complete the job in 4 days and R can complete the job in 6 days. How many days the shopkeeper will it take to complete the job if all the machines are used simultaneously ?
A can write 32 pages in 6 hours and B can write 40 pages in 5 hours. If they write together, in how many hours they can write 110 pages ?

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion