`140%of ?=13xx400-780`

Options

A. 3157
B. 3157.14
C. 3517
D. 3715

Answer

To solve the equation \( 140\% \text{ of } ? = 13 \times 400 - 780 \), we will follow these steps:

### Step 1: Convert the percentage to a fraction
140% can be expressed as a fraction:
\[ 140\% = \frac{140}{100} = \frac{14}{10} = 1.4 \]

### Step 2: Set up the equation
We can rewrite the equation using the fraction we found:
\[ 1.4 \times ? = 13 \times 400 - 780 \]

### Step 3: Calculate the right side of the equation
First, calculate \( 13 \times 400 \):
\[ 13 \times 400 = 5200 \]
Now, subtract 780 from 5200:
\[ 5200 - 780 = 4420 \]

### Step 4: Substitute back into the equation
Now we have:
\[ 1.4 \times ? = 4420 \]

### Step 5: Solve for ?
To find the value of ?, divide both sides by 1.4:
\[ ? = \frac{4420}{1.4} \]

### Step 6: Perform the division
Calculating \( \frac{4420}{1.4} \):
\[ ? = 3150 \]

### Final Answer
The value of the question mark is:
\[ ? = 3150 \]

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