`30% of 140 = ?% of 840`

Options

A. 5
B. 15
C. 24
D. 60

Answer

To solve the question "30% of 140 = ?% of 840", we can follow these steps:

### Step 1: Write the equation
We start by expressing the given information in an equation format. We know that:
\[ 30\% \text{ of } 140 = x\% \text{ of } 840 \]

### Step 2: Convert percentages to fractions
Convert the percentages into fractions:
\[ \frac{30}{100} \times 140 = \frac{x}{100} \times 840 \]

### Step 3: Simplify the equation
We can simplify the equation by multiplying both sides by 100 to eliminate the denominators:
\[ 30 \times 140 = x \times 840 \]

### Step 4: Calculate 30% of 140
Now, we calculate \( 30 \times 140 \):
\[ 30 \times 140 = 4200 \]

So, we have:
\[ 4200 = x \times 840 \]

### Step 5: Solve for x
Now, we can solve for \( x \) by dividing both sides by 840:
\[ x = \frac{4200}{840} \]

### Step 6: Simplify the division
Now, we simplify \( \frac{4200}{840} \):
- First, we can simplify by dividing both the numerator and denominator by 280:
\[ \frac{4200 \div 280}{840 \div 280} = \frac{15}{3} \]

- Now, simplifying \( \frac{15}{3} \):
\[ 15 \div 3 = 5 \]

### Final Answer
Thus, \( x = 5 \). Therefore, the answer is:
\[ 30\% \text{ of } 140 = 5\% \text{ of } 840 \]