If the operation $\wedge$ is defined by the equation $x \wedge y = 2x + y$, what is the value of $a$ in $2 \wedge a = a \wedge 3$?
Aptitude
Simplification
Difficulty: Easy
Choose an option
-
A0
-
B$-1$
-
C1
-
D4
Answer
Correct Answer: 1
Explanation
### Concept & Formula
This problem requires setting up a linear equation by expanding both sides of an equality using a provided custom operation rule.
$$x \wedge y = 2x + y$$
### Step-by-Step Solution
* **Expand the left side ($2 \wedge a$):**
Using the rule where $x = 2$ and $y = a$:
$$2 \wedge a = 2(2) + a = 4 + a$$
* **Expand the right side ($a \wedge 3$):**
Using the rule where $x = a$ and $y = 3$:
$$a \wedge 3 = 2(a) + 3 = 2a + 3$$
* **Equate and solve for $a$:**
The problem states that $2 \wedge a = a \wedge 3$.
$$4 + a = 2a + 3$$
Subtract $a$ from both sides:
$$4 = a + 3$$
Subtract 3 from both sides:
$$1 = a$$
### Exam Strategy & Shortcut
For linear single-variable equations derived from custom operations, simply plug in the options directly into the expanded equation $4 + a = 2a + 3$ if the algebra feels slow.
Test option (c) $a = 1$: $4 + 1 = 5$ on the left; $2(1) + 3 = 5$ on the right. Both sides match instantly.
### Common Pitfall
Assuming the operation $\wedge$ is commutative (i.e., that $x \wedge y = y \wedge x$) and therefore concluding $a$ must be 2. The definition $2x + y$ heavily weights the first operand, meaning order matters immensely.
### Final Answer
**Therefore, the correct answer is 1.**