A and B together can do a work in 6 days. C and B can finish the same job in \(\frac{60}{7}\) days. A started the work and worked for 3 days. B and C continued for 6 days, then the difference of days in which C & A can complete the job is?

10 days

(B + C)'s 6 days work = 6 × 7 = 42

  Remaining work = 60 - 42 = 18

This is done by A in 3 days

Hence efficiency of A = \(\frac{18}{3}\) = 6

 A + B = 10 (Eff.)

 6 + B = 10

B = 4 (Eff.)

B + C = 7 (Eff.)

4 + C = 7

  C = 3 (Eff.)

A finishes the work in = \(\frac{60}{6}\) = 10 days

C finishes the work in = \(\frac{60}{3}\) = 20 days

Difference (C- A) = 20 - 10 = 10 days