Find: a. `15%` of Rs 250 b. `18%` of 900km

Answer

### Step-by-Step Solution

**Part a: Find 15% of Rs 250**

1. **Understand the percentage**: We need to find 15% of Rs 250.

2. **Convert percentage to decimal**:
- 15% can be written as \( \frac{15}{100} \).

3. **Calculate 15% of Rs 250**:
- To find 15%, we multiply Rs 250 by \( \frac{15}{100} \):
\[ 15\% \text{ of } 250 = 250 \times \frac{15}{100} \]

4. **Simplify the calculation**:
- First, calculate \( \frac{250}{100} \):
\[ \frac{250}{100} = 2.5 \]
- Now multiply by 15:
\[ 15 \times 2.5 = 37.5 \]

5. **Conclusion for part a**:
- Therefore, 15% of Rs 250 is Rs 37.5.

---

**Part b: Find 18% of 900 km**

1. **Understand the percentage**: We need to find 18% of 900 km.

2. **Convert percentage to decimal**:
- 18% can be written as \( \frac{18}{100} \).

3. **Calculate 18% of 900 km**:
- To find 18%, we multiply 900 km by \( \frac{18}{100} \):
\[ 18\% \text{ of } 900 = 900 \times \frac{18}{100} \]

4. **Simplify the calculation**:
- First, calculate \( \frac{900}{100} \):
\[ \frac{900}{100} = 9 \]
- Now multiply by 18:
\[ 18 \times 9 = 162 \]

5. **Conclusion for part b**:
- Therefore, 18% of 900 km is 162 km.

---