The LCM of two numbers is 30 and their HCF is 5. One of the numbers is 10. The other is number will be.

Options

A. 5
B. 25
C. 15
D. 225

Answer

To find the other number given that the LCM of two numbers is 30, their HCF is 5, and one of the numbers is 10, we can use the relationship between LCM, HCF, and the two numbers.

### Step-by-Step Solution:

1. **Understand the relationship between LCM, HCF, and the two numbers**:
The relationship is given by the formula:
\[ \text{LCM} \times \text{HCF} = \text{Number 1} \times \text{Number 2} \]

2. **Identify the known values**:
We know:
- LCM = 30
- HCF = 5
- Number 1 = 10
- Number 2 = X (the number we need to find)

3. **Substitute the known values into the formula**:
Using the formula from step 1, we substitute the known values:
\[ 30 \times 5 = 10 \times X \]

4. **Calculate the left side**:
Calculate \(30 \times 5\):
\[ 150 = 10 \times X \]

5. **Solve for X**:
To find X, divide both sides by 10:
\[ X = \frac{150}{10} = 15 \]

6. **Conclusion**:
The other number is 15.

### Final Answer:
The other number is **15**.