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:

$\frac{3}{4}$ $\frac{5}{8}$ $\frac{1}{4}$ $\frac{5}{7}$

$\frac{1}{4}$

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 = \(\frac{60 - 45}{60}\) = \(\frac{15}{60}\) = \(\frac{1}{4}\).