A can complete a piece of work in 12 days while B can do the same work in 18 days. If they both work together, then how many days will be required to finish the work?
- A6.5
- B6
- C7
- D7.2
Solution & Step-by-step Explanation
Let the total work be the LCM of 12 and 18.
Total Work=LCM(12,18)=36units
Calculate the efficiencies (work done per day):
Efficiency of A=
12
36
=3units/day
Efficiency of B=
18
36
=2units/day
Combined efficiency of A and B:
Total Efficiency=3+2=5units/day
Time required to finish the work together:
Time=
Total Efficiency
Total Work
=
5
36
=7.2days
Total Work=LCM(12,18)=36units
Calculate the efficiencies (work done per day):
Efficiency of A=
12
36
=3units/day
Efficiency of B=
18
36
=2units/day
Combined efficiency of A and B:
Total Efficiency=3+2=5units/day
Time required to finish the work together:
Time=
Total Efficiency
Total Work
=
5
36
=7.2days