Question 228 of 480
Find the value of m if 13m + 24m = 41m
Correct Answer:
B
Explanation
To solve the equation \( 13_m + 24_m = 41_m \), we need to understand what the notation \( x_m \) means. The subscript \( m \) indicates that the numbers are in base \( m \).
### Step 1: Convert the numbers from base \( m \) to base 10
1. **Convert \( 13_m \) to base 10**:
- The number \( 13_m \) can be expressed in base 10 as:
\[
1 \cdot m^1 + 3 \cdot m^0 = m + 3
\]
2. **Convert \( 24_m \) to base 10**:
- The number \( 24_m \) can be expressed in base 10 as:
\[
2 \cdot m^1 + 4 \cdot m^0 = 2m + 4
\]
3. **Convert \( 41_m \) to base 10**:
- The number \( 41_m \) can be expressed in base 10 as:
\[
4 \cdot m^1 + 1 \cdot m^0 = 4m + 1
\]
### Step 2: Set up the equation in base 10
Now we can rewrite the original equation \( 13_m + 24_m = 41_m \) in base 10:
\[
(m + 3) + (2m + 4) = 4m + 1
\]
### Step 3: Simplify the equation
Combine like terms on the left side:
\[
m + 3 + 2m + 4 = 4m + 1
\]
This simplifies to:
\[
3m + 7 = 4m + 1
\]
### Step 4: Solve for \( m \)
Now, we will isolate \( m \):
1. Subtract \( 3m \) from both sides:
\[
7 = 4m - 3m + 1
\]
This simplifies to:
\[
7 = m + 1
\]
2. Subtract 1 from both sides:
\[
7 - 1 = m
\]
Thus, we find:
\[
m = 6
\]
### Conclusion
The value of \( m \) is **6**. Therefore, the correct option is **B**.
### Explanation of Other Options
- **Option A (8)**: If \( m = 8 \), then the left side would be \( 13_8 + 24_8 \) which equals \( 11 + 20 = 31 \) in base 10, while the right side \( 41_8 \) equals \( 33 \) in base 10. This does not satisfy the equation.
- **Option C (5)**: If \( m = 5 \), then \( 13_5 + 24_5 \) equals \( 8 + 14 = 22 \) in base 10, while \( 41_5 \) equals \( 21 \) in base 10. This does not satisfy the equation.
- **Option D (2)**: If \( m = 2 \), then \( 13_2 + 24_2 \) equals \( 3 + 6 = 9 \) in base 10, while \( 41_2 \) equals \( 5 \) in base 10. This does not satisfy the equation.
### Revision Summary
- Convert numbers from base \( m \) to base 10 for clarity.
- Combine like terms to simplify the equation.
- Isolate \( m \) to find its value.
- Check each option to confirm correctness and eliminate incorrect choices.