Find the value of question mark (?) in the following questions.
`? + 13 xx 50 = 420 + "45% of 800" + 220`

Options

A. 300
B. 350
C. 400
D. 450

Answer

To find the value of the question mark (?) in the equation:

\[ ? + 13 \times 50 = 420 + 45\% \text{ of } 800 + 220 \]

Let's solve it step by step.

### Step 1: Calculate \( 13 \times 50 \)
First, we need to calculate the multiplication on the left side of the equation.

\[ 13 \times 50 = 650 \]

### Step 2: Rewrite the equation
Now, we can rewrite the equation with the calculated value:

\[ ? + 650 = 420 + 45\% \text{ of } 800 + 220 \]

### Step 3: Calculate \( 45\% \text{ of } 800 \)
Next, we need to calculate \( 45\% \text{ of } 800 \):

\[ 45\% \text{ of } 800 = \frac{45}{100} \times 800 = 360 \]

### Step 4: Substitute back into the equation
Now substitute this value back into the equation:

\[ ? + 650 = 420 + 360 + 220 \]

### Step 5: Calculate the right side
Now, let's calculate the right side of the equation:

\[ 420 + 360 + 220 = 1000 \]

### Step 6: Set up the equation for ?
Now we have:

\[ ? + 650 = 1000 \]

### Step 7: Solve for ?
To find the value of ?, we subtract 650 from both sides:

\[ ? = 1000 - 650 \]

\[ ? = 350 \]

Thus, the value of the question mark (?) is **350**.