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