The cost of 1 metre of ribbon is rs. 35.80. What will be the cost of 9.8 metres of ribbon?

Options

A. 450.84
B. 350.84
C. 360.84
D. 359.84

Answer

To find the cost of 9.8 metres of ribbon when the cost of 1 metre is Rs. 35.80, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the cost of 1 metre of ribbon**:
The cost of 1 metre of ribbon is given as Rs. 35.80.

2. **Set up the multiplication**:
To find the cost of 9.8 metres, we need to multiply the cost of 1 metre by the number of metres:
\[ \text{Cost of 9.8 metres} = 9.8 \times 35.80 \]

3. **Remove the decimal for easier multiplication**:
Since 9.8 has one decimal place and 35.80 has two decimal places, we can first convert them to whole numbers by multiplying both by 100 (to eliminate the decimals):
\[ 9.8 \times 100 = 980 \quad \text{and} \quad 35.80 \times 100 = 3580 \]
Now, we will multiply:
\[ 980 \times 3580 \]

4. **Perform the multiplication**:
Now we calculate \( 980 \times 3580 \):
\[ 980 \times 3580 = 3508400 \]

5. **Adjust for the decimal places**:
Since we multiplied both numbers by 100, we need to divide the result by 100 (to account for the two decimal places we removed):
\[ \frac{3508400}{100} = 35084 \]

6. **Place the decimal in the correct position**:
The original multiplication involved 3 decimal places (1 from 9.8 and 2 from 35.80). Therefore, we place the decimal point two digits from the right:
\[ 35084 \rightarrow 350.84 \]

7. **Final answer**:
The cost of 9.8 metres of ribbon is Rs. 350.84.

### Final Answer:
The cost of 9.8 metres of ribbon is Rs. 350.84.

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