Time and Work Questions

Q:

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 ?

A) 7 hrs B) 6 hrs 10 min
C) 5 hrs 25min D) 8 hrs 15 min
 
Answer & Explanation Answer: D) 8 hrs 15 min

Explanation:

A can write in 1hour = 32/6 pages
similarly
B in 1 hour = 40/5 pages

Together (A+B) in 1 hour = 32/6 + 40/5 = 40/3
so,
A+B write 40/3 pages in 1 hour
A+B write 110 pages in (3/40) x 110 Hours = 8 hours 15 min.

Report Error

View Answer Workspace Report Error Discuss

2 258
Q:

A does half as much work as Band C does half as much work as A and B together. If C alone can finish the work in 40 days, then together ,all will finish the work in  ?

A) 17 + 4/7 days B) 13 + 1/3 days
C) 15 + 3/2 days D) 16 days
 
Answer & Explanation Answer: B) 13 + 1/3 days

Explanation:

C alone can finish the work in 40 days.
As given C does half as much work as A and B together
=> (A + B) can do it in 20 days
(A + B)s 1 days wok = 1/20.
A's 1 days work : B's 1 days Work = 1/2 : 1 = 1:2(given)
A's 1 day’s work = (1/20) x (1/3) = (1/60) [Divide 1/20 in the raio 1:2]
B's 1 days work = (1/20) x (2/3) = 1/30
(A+B+C)'s 1 day's work = (1/60) + (1/30) + (1/40) = 9/120 = 3/40

All the three together will finish it in 40/3 = 13 and 1/3 days.

Report Error

View Answer Workspace Report Error Discuss

3 256
Q:

50 men can build a tank in 40days, but though they begin the work together, 5 men quit every ten days. The time needed to build the tank is ?

A) 50 days B) 48 days
C) 47.5 days D) 49 days
 
Answer & Explanation Answer: A) 50 days

Explanation:

50 men can build a tank in 40 days
Assume 1 man does 1 unit of work in 1 day
Then the total work is 50×40 = 2000 units

50 men work in the first 10 days and completes 50×10 = 500 units of work
45 men work in the next 10 days and completes 45×10 = 450 units of work
40 men work in the next 10 days and completes 40×10 = 400 units of work
35 men work in the next 10 days and completes 35×10 = 350 units of work
So far 500 + 450 + 400 + 350 = 1700 units of work is completed and

remaining work is 2000 - 1700 = 300 units

30 men work in the next 10 days. In each day, they does 30 units of work.

Therefore, additional days required = 

Thus, total 10+10+10+10+10 = 50 days required.

Report Error

View Answer Workspace Report Error Discuss

9 242
Q:

4 men can repair a road in 7 hours. How many men are required to repair the road in 2 hours ?

A) 17 men B) 14 men
C) 13 men D) 16 men
 
Answer & Explanation Answer: B) 14 men

Explanation:

M x T / W = Constant
where, M= Men (no. of men)
T= Time taken
W= Work load
So, here we apply
M1 x T1/ W1 = M2 x T2 / W2
Given that, M1 = 4 men, T1 = 7 hours ; T2 = 2 hours, we have to find M2 =?
Note that here, W1 = W2 = 1 road, ie. equal work load.
Clearly, substituting in the above equation we get, M2 = 14 men.

Report Error

View Answer Workspace Report Error Discuss

2 229
Q:

A contractor undertook to complete a piece of work in 120 Days and employed 140 men upon it. At the end of 66 days only half of the work was done,so he put on 25 extra men. By how much time did he exceed the specific time ?

A) 2 days B) 3 days
C) 4 days D) 5 days
 
Answer & Explanation Answer: A) 2 days

Explanation:

work done=total number of person x number of days;
half of work done = 140 x 66;
For half of remaining work 25 extra men are added.
Therefore, total men for half work remaining = 140 + 25 = 165;
Let 2nd half work will be completed in K days;
140 x 66 = 165 x K
K = 122;
Hence, extra days => 122-120 = 2days.

Report Error

View Answer Workspace Report Error Discuss

1 193