P and B can do the work in 10 and 15 days, respectively. 

Let the total units of work be LCM(10,15) = 30 units.

So, P can do 30/10= 3 units per day

B can do 30/15 = 2 units per day

If they work together, they would do 3+2 =5 units per day.

Therefore, in 5 days, they will do $$5\times\ 5=25\ $$units

Then Work left = 30-25 = 5 units.

R can do this work in 2 days, therefore he does 5/2 = 2.5 units per day.

If they are getting Rs.1500 for 30 units of work, then they get $$\ \frac{\ 1500}{30}=Rs.\ 50$$ per unit.

B and R will do 2 + 2.5 = 4.5 units per day. 

Therefore, they will earn $$4.5\times\ 50$$= Rs. 225