Work & Time

Work & Time

If a man can do a piece of work in x days, then the work done by a man in one day is 1/x.
eg. if a man can do a work in 8 days, then the work done by a man in one day is 1/8.
 
If the work done by a man in one day is 1/x, then he will complete the work in x days.
eg. if a man's one day work is 1/7, then he will complete the work in 7 days.
 
If the efficiency of A is x times that of B, then the time taken by A is 1/x times that of B
 
If A and B do a work in different time, then (A's work):(B's work)= (Time taken by B):(Time taken by A)

 

Questions Asked from this Chapter:

 

Question Type 1: Based on basic concepts of Time & Work

Example:

A and B can do a work in 12 day, B and C in 8 days and C and A in 6 days. In how many days B alone can do this work?
a) 24 days
b) 32 days
c) 40 days
d) 48 days
Solution:

Question Type 2: "A" can do a work in "X" days and "B" can do a work in "Y" days. They work together for "M" days. Then one of them leaves and other complete work in "N" days

Example:

A and B can do a job in 6 and 12 days respectively. They began the work together but A leaves after 3 days. Then the total number of days needed for the completion of the work is:
a) 4
b) 5
c) 6
d) 9
Solution:

Question Type 3: Based on "M" man, "N" women and "P" Boys

Example:

3 men or 5 women can do a work in 12 days. How long will 6 men and 5 women take to finish the work?
a) 20
b) 10
c) 4
d) 15
Solution:

Question Type 4: Based on Fraction of Work

Example:
A completes 7/10 of a work in 15 days, then he complete the remaining work with the help of B in 4 days. The time required for A and B together to complete the entire work is:
a) 10.5 days
b) 12*(2/3) days
c) 13*(1/3) days
d) 8.25 days
Solution:

Question Type 5: "A" is 'N' times or percent more efficient worker than "B"

Example:

A can do a certain work in 12 days. B is 60% more efficient than A. How many days will B and A together take to do the same jobs?
a) 80/13
b) 70/13
c) 75/13
d) 60/13
Solution:

Question Type 6: Based on M1 X D1 X W1 = M2 X D2 X W2

Example:

If 80 persons can finish a work within 16 days by working 6 hours a day, the number of hours a day, should 64 person work to finish that very job within 15 days is:
a) 5 hours
b) 7 hours
c) 8 hours
d) 6 hours
Solution: