SSC MTS 5 Aug 2019 Shift 2 Paper

A = 10 days
⇒ A + B = 20/3 days
⇒ A + B + C = 40/7 days
L.C.M. of 10, 20/3 and 40/7 is 40 (total work).
⇒ Efficiency of A = 40 ÷ 10 = 4 ---- (1)
⇒ Efficiency of A + B = 40 ÷ 20/3 = 6
⇒ Efficiency of A + B + C = 40 ÷ 40/7 = 7 ---- (2)
From (2) – (1)
⇒ Efficiency of B + C = 7 – 4 = 3
⇒ B and C together do the same piece of work = 40/3 days
∴ B and C together do the same piece of work in 40/3 days.