George can do a piece of work in 8 hours. Paul can do the same work in 10 hours, Hari can do the same work in 12 hours. George, paul and hari start the same work at 9 am, while george stops at 11 am, the remaining two complete the work. What time will the work complete?
Answers
George can do the work in 8 hours
⇒ 1 hour = 1/8 of the work
Paul can do the work in 10 hours
⇒1 hour = 1/10 of the work
Hari can do the work in 12 hours
⇒ 1 hour = 1/12 of the work
Find the amount of work that can be completed in an hour:
⇒ 1 hour = 1/8 + 1/10 + 1/12 = 37/120
Find the amount amount of work completed in 2 hours (9 am to 11 am):
⇒ 1 hour = 37/120
⇒2 hours = 37/120 x 2 = 37/60
Find the amount of work remain:
Work remain = 1 - 37/60 = 23/60
Find the amount of work Paul and Hari can do in an hour:
1 hour = 1/10 + 1/12 = 11/60
Find the number of hours needed for them to complete the rest of the work:
Number of hours needed = 23/60 ÷ 11/60 = 2.09 hours = 2 hours
Find the time the work is completed:
11am + 2 hours = 1 pm
Answer: They will complete the work at 1 pm.
Answer:
lcm of 8,10,12 is 120
efficiency of :
George is 15
Paul is 12
hari is 10
then
all the 3 work in first 2 hrs
2(15+12+10)+x(12+10)=120
x=2.09
tot time from 9 am is 4.09 or 4
so 1 pm