P and Q can complete a work in 24 days and 36 days,

Solution

Let the total work be LCM of (24, 36 and 12) = 72 units Number of units of work done by P alone in one day = 72/24 = 3 units Number of units of work done by Q alone in one day = 72/36 = 2 units Number of units of work done by P, Q and R together in one day = 72/12 = 6 units Number of units of work done by R alone in one day = 6 – 3 – 2 = 1 unit So, time taken by R alone to complete the work = 72/1 = 72 days So, per day wage of R = 6120/72 = Rs. 85