From the above diagram it is clear that efficiency of C and D is 7.5%, since C and D completes 60% work in 8 days and efficiency of B,C and D is 20%. It means efficiency of B alone is 12.5% = (20 − 7.5) % Now
C
:
D
Numberofdays
4x
:
5x
Efficiency
5y
:
4y
∴ Efficiency of C =
5
9
×7.5=4.16% and Efficiency of D =
4
9
×7.5=3.33% Thus, D is the least efficient person. Now share of work done by David (D) = 3.33% × 10 = 33.33% Hence, his share of amount = 33.33% of ₹ 3000 = ₹ 1000