Question

Ram and Shyam works on a job together and finish 60% of it. Ram then takes leave and Shyam works for eight more days to complete the work. How long will it take Ram to complete the work?

• A. $50$
• B. $60$
• C. $70$
• D. $80$

Answer 1

Answer: (B)

$60$

Ram and Shyam can complete the work in $15$days.
Percentage of work done by both in one day $=100/15=6.66$$
Shyam alone can complete the whole work in $20$ days.
So, percentage of work done by b in one day $=100/20=5\%$
Percentage of work done by a in one day $=6.66-5=1.66\%$
Thus, a can complete the whole work alone in $=100/1.66=60$ days (approx)
Alternatively,
a and b can complete the work in = 15 days
Part of work done by a and b in one day= 1/15
b can complete the work alone in = 20 days.
so, part of work done by b in one day = 1/20
Part of work done by a = 1/15 - 1/20= 1/60
a can complete the work in = 1/(1/60) = 60 days.