Let the work = 48 units (LCM 16, 12)
Efficiency of P = 48/16 = 3 units/day
Also, P + Q = 48/12 = 4 units/day
Hence, Efficiency of Q = 4 - 3 = 1 unit/day
Money should be divided in the ratio of their efficiencies
Hence, share of Q = 1/4 × 500 = Rs. 125