A, B and C get ₹ 5400 for doing a work in 36 days. A and C get ₹ 1880 for doing the same work in 20 days, while B and C get ₹ 3040 for doing the same work in 40 days. Find the amount received by C per day.

Amount received by ( A + B + C) per day
= 5400/36 = ₹ 150
∴ A + B + C = ∴ 150.................(i)
Similarly, amount received by (A + C) per day
= 1880/20 = ₹ 94
∴ A + C = ₹ 94 ........................(ii)
Amount received by (B + C) per day
= 3040/40 = ₹ 76
∴ B + C = ₹ 76 ........................(iii)
From Eqs. (i) and (iii), we get
A + 76 = ₹ 150
A = 150 - 76 = ₹ 74
By putting the value of A in Eq. (ii), we get
74 + C = ₹ 94
∴ C = 94 - 74 = ₹ 20
Hence, amount received by C per day
= ₹ 20