A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 4 days B had to leave. Then A working with a new worker C completed the remaining work in 3 days. If C works alone, in how many days he can do 40% of the same work?
Answer & explanation
Correct answer: option 1
A = 15 days, B = 10 days,
⇒ A + B worked for 4 days together = (2 + 3) x 4 = 20 units ..(Efficiency × Days = Total work)
⇒ B left and replaced by C,
So, A + C completed the remaining work in 3 days.
⇒ Remaining work = 30 -20 = 10 units.
⇒ \(\frac{10}{2 + C}\) = 3 .. (\(\frac{Work}{Efficiency}\) = Time)
⇒ 10 = 6 + 3C
⇒ 3C = 4
⇒ C = \(\frac{4}{3}\).
⇒ 40% of 30 = 12 units.
⇒ Time taken by C to complete 40% of the total work =
$\frac{12}{\frac{4}{3}}$=\(\frac{12 * 3}{4}\)= 9 days.