Pawan kaul earns 15 percent on an investment but loses 10 percent on another investment. If the ratio of two investments is 3 : 5, then the combined loss percent is = ?

Answer: Option D

Let the total first investment is 300 and the second is 500.
Total Investment = 300 + 500 = 800
15% profit on 1^st investment = 300 + 15% of 300 = 300 + 45 = 345
10% loss on 2^nd investment = 500 - 10% of 500 = 500 - 50 = 450
Now total amount = 345 + 450 = 795
Total loss = 800 - 795 = 5
% loss = $$\frac{5}{800}\times 100=\frac{5}{8}\%$$
∴ % loss = $$\frac{5}{8}\%$$