A can do a work in 12 days and B can do the same work in 16 days. If they work in it together for 4 days, then the fraction of the work that is left is :

$\frac{3}{5}$ $\frac{9}{16}$ $\frac{5}{12}$ $\frac{7}{8}$

$\frac{5}{12}$

A = 12 days, B = 16 days, ⇒ A + B worked for 4 days = (4 + 3) x 4 = 7 x 4 = 28 units,   ..(Efficiency × Days = Total work) ⇒ Fraction of work left = \(\frac{48-28}{48}\) = \(\frac{20}{48}\) = \(\frac{5}{12}\)