A can do a piece of work alone in 15 days, while B complete the same piece of work alone in 12 days. If they work on it together for 5 days, then the fraction of the work that will be left is:
Answer & explanation
Correct answer: option 3
A = 15 days, B = 12 days,
⇒ A + B worked for 5 days = (4 + 5) x 5 = 9 x 5 = 45 units,
⇒ Fraction of work left = \(\frac{60 - 45}{60}\) = \(\frac{15}{60}\) = \(\frac{1}{4}\).