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?
A. 6
B. 8
C. 10
D. 12
Answer: Option B
Solution (By Examveda Team)
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 daysThis Question Belongs to Arithmetic Ability >> Time And Work
R one day work=1/20
R 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