If 90% of x is 315 km, then the value of x is

Options

A. 325 km
B. 350 km
C. 350 m
D. 325 m

Answer

To find the value of \( x \) given that 90% of \( x \) is 315 km, we can follow these steps:

### Step 1: Set up the equation
We know that 90% of \( x \) can be expressed mathematically as:
\[ \frac{90}{100} \times x = 315 \]

### Step 2: Simplify the percentage
To simplify, we can rewrite 90% as a fraction:
\[ 0.9 \times x = 315 \]

### Step 3: Solve for \( x \)
To isolate \( x \), divide both sides of the equation by 0.9:
\[ x = \frac{315}{0.9} \]

### Step 4: Convert the division
To make the division easier, we can multiply both the numerator and the denominator by 10:
\[ x = \frac{315 \times 10}{0.9 \times 10} = \frac{3150}{9} \]

### Step 5: Perform the division
Now, we can divide 3150 by 9:
\[ x = 350 \]

### Conclusion
Thus, the value of \( x \) is:
\[ \boxed{350 \text{ km}} \]

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