A, B and C can individually complete a piece of work in 24 days, 15 days and 12 days, respectively. B and C started the work and worked for 3 days and left. The number of days required by A alone to complete the remaining work, is:

$13\frac{1}{5}$

A = 24 days, B = 15 days, C = 12 days,

⇒ B + C worked for 3 days = (8 + 10) x 3 = 54 units.  ..(Efficiency × Days = Total work)

⇒ Remaining work = 120 - 54 = 66 units.

⇒ Time taken by A to complete the remaining work = \(\frac{66}{5}\) = \( {13 }_{ 5}^{1 } \) days.        ..(\(\frac{Work}{Efficiency}\) = Time)