Out of total capital required to start a business A invested 30%, B invested $$\frac{2}{5}$$ th and C invested the remaining capital. At the end of one year sum of Rs. 4000 is earned as a profit which is 20% of the capital given by B, then find how much C invested in the business ?
Correct Answer: Rs. 15000
Total profit = Rs. 4000
According to the question,
$$\eqalign{ & {\text{20% of B's capital}} = {\text{Rs}}{\text{.}}\,{\text{4000}} \cr & {\text{1% of B's capital}} = {\text{Rs}}{\text{.}}\,\frac{{{\text{4000}}}}{{20}} \cr & {\text{B's total capital}} \cr & = {\text{Rs}}{\text{. }}\frac{{{\text{4000}}}}{{20}} \times 100 \cr & = {\text{Rs}}{\text{. }}20000 \cr} $$
Let total capital required for business = 100 units.
Hence, Required capital for C = Rs. 15000
According to the question,
$$\eqalign{ & {\text{20% of B's capital}} = {\text{Rs}}{\text{.}}\,{\text{4000}} \cr & {\text{1% of B's capital}} = {\text{Rs}}{\text{.}}\,\frac{{{\text{4000}}}}{{20}} \cr & {\text{B's total capital}} \cr & = {\text{Rs}}{\text{. }}\frac{{{\text{4000}}}}{{20}} \times 100 \cr & = {\text{Rs}}{\text{. }}20000 \cr} $$
Let total capital required for business = 100 units.
| A | : | B | : | C | |
| Capital | 30 | : | 40 | : | 30 |
| × 500 | : | × 500 | : | × 500 | |
| 15000 | : | 20000 | : | $$\boxed{15000}$$ |