P + Q = (5050 × 2) = 10100 ...1 Q + R = (6250 × 2) = 12500 ...2 P + R = (5200 × 2) = 10400 ...3 We have three equations and three unknowns. Then, by simplifying these three equations we get: P's income = Rs. 4000 Q's income = Rs. 6100 R's income = Rs. 6400