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Raj can do a piece of work in 20 days. He started the work and left after some days, when 25% work was done. After it Abhijit joined and completed it working for 10 days. In how many days Raj and Abhijit can do the complete work, working together?
Answer & Solution
Correct Answer:
Option
B
Efficiency of Raj = $$\frac{{100}}{{20}}$$ = 5%
Work completed by Raj = 25%
Rest work = 75%
Efficiency of Abhijit = $$\frac{{75}}{{10}}$$ = 7.5%
Combined efficiency = 5 + 7.5 = 12.5%
They will complete the whole work by working together in,= $$\frac{{100}}{{12.5}}$$ = 8 days
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LoginR completes 25% that is 1/4 of work and leaves
x*(1/20)=1/4
x is no. of days to complete 1/4 of work
x=5
remaining work left=1-(1/4)=3/4 work
3/4 work is completed by A in 10 days
1 work is completed by A in 40/3 days
R+A=1/20+(1/(40/3))
=1/20+(3/40)
=5/40
=1/8
R+A=8 days