The equations have become wrong because of the wrong order of signs. Choose the correct order of signs from the four options given below so as to make the equations right. Write the alternative number of the correct option on the answer sheet against the corresponding question number-
`15 = 5 + 2 xx 1 divide 7`

Options

A. `xx divide + =`
B. `+ xx divide =`
C. `+ divide = xx`
D. `divide xx + =`

Answer

To solve the equation \( 15 = 5 + 2 \times 1 \div 7 \) and find the correct order of operations, we need to evaluate the four options provided.

### Step-by-Step Solution:

1. **Understanding the Original Equation**:
The original equation is \( 15 = 5 + 2 \times 1 \div 7 \). We need to check if this equation is true or false.

2. **Evaluating the Right-Hand Side (RHS)**:
We will evaluate the RHS using the current order of operations (multiplication and division before addition):
\[ 5 + 2 \times 1 \div 7 \]
- First, calculate \( 2 \times 1 = 2 \).
- Then, perform the division: \( 2 \div 7 = \frac{2}{7} \).
- Now, add \( 5 + \frac{2}{7} = 5 + 0.2857 \approx 5.2857 \).
- Thus, the RHS is approximately \( 5.2857 \), which is not equal to \( 15 \).

3. **Checking Each Option**:
We will now check each option to see which one makes the equation true.

**Option 1**: \( 15 \times 5 = 2 + 1 = 7 \)
- LHS: \( 15 \times 5 = 75 \)
- RHS: \( 2 + 1 = 3 \)
- \( 75 \neq 3 \) (Incorrect)

**Option 2**: \( 15 + 5 \times 2 \div 1 = 7 \)
- LHS: \( 15 + 5 \times 2 = 15 + 10 = 25 \)
- RHS: \( 25 \div 1 = 25 \)
- \( 25 \neq 7 \) (Incorrect)

**Option 3**: \( 15 + 5 \div 2 = 7 \)
- LHS: \( 5 \div 2 = 2.5 \)
- RHS: \( 15 + 2.5 = 17.5 \)
- \( 17.5 \neq 7 \) (Incorrect)

**Option 4**: \( 15 \div 5 \times 2 + 1 = 7 \)
- LHS: \( 15 \div 5 = 3 \)
- Then, \( 3 \times 2 = 6 \)
- Finally, \( 6 + 1 = 7 \)
- \( 7 = 7 \) (Correct)

4. **Conclusion**:
The correct option that makes the equation true is **Option 4**.