Question 7 of 480
If 2\(_9\) x (Y3)\(_9\) = 3\(_5\) x (Y3)\(_5\), find the value of Y.
Correct Answer:
C
Explanation
To solve the equation \(2_9 \times (Y3)_9 = 3_5 \times (Y3)_5\), we need to first understand what the numbers in different bases mean and how to convert them to a common base (usually base 10) for easier calculations.
### Step 1: Convert the numbers from their respective bases to base 10.
1. **Convert \(2_9\) to base 10:**
- In base 9, \(2_9\) is simply \(2\) in base 10.
2. **Convert \((Y3)_9\) to base 10:**
- The number \((Y3)_9\) can be expressed as:
\[
Y \times 9^1 + 3 \times 9^0 = 9Y + 3
\]
3. **Convert \(3_5\) to base 10:**
- In base 5, \(3_5\) is simply \(3\) in base 10.
4. **Convert \((Y3)_5\) to base 10:**
- The number \((Y3)_5\) can be expressed as:
\[
Y \times 5^1 + 3 \times 5^0 = 5Y + 3
\]
### Step 2: Substitute the base 10 values into the equation.
Now we can rewrite the original equation using the base 10 conversions:
\[
2 \times (9Y + 3) = 3 \times (5Y + 3)
\]
### Step 3: Expand both sides of the equation.
1. **Left side:**
\[
2 \times (9Y + 3) = 18Y + 6
\]
2. **Right side:**
\[
3 \times (5Y + 3) = 15Y + 9
\]
### Step 4: Set the two sides equal to each other.
Now we have:
\[
18Y + 6 = 15Y + 9
\]
### Step 5: Solve for \(Y\).
1. Subtract \(15Y\) from both sides:
\[
18Y - 15Y + 6 = 9
\]
This simplifies to:
\[
3Y + 6 = 9
\]
2. Subtract \(6\) from both sides:
\[
3Y = 3
\]
3. Divide both sides by \(3\):
\[
Y = 1
\]
### Conclusion:
The value of \(Y\) is \(1\). Therefore, the correct option is **D. 1**.
### Explanation of Other Options:
- **Option A (4):** If \(Y = 4\), substituting back into the equation would not satisfy the equality, as the left side would be larger than the right side.
- **Option B (3):** If \(Y = 3\), substituting back would also not satisfy the equality, as the left side would again be larger than the right side.
- **Option C (2):** If \(Y = 2\), substituting back would yield a left side that is still larger than the right side, thus not satisfying the equation.
### Revision Summary:
- Convert numbers from their respective bases to base 10 for easier calculations.
- Set the equation after conversion and simplify it step by step.
- Solve for the variable by isolating it on one side of the equation.
- Check each option by substituting back into the original equation to verify correctness.
This methodical approach ensures clarity and accuracy in solving base conversion problems in mathematics.