Question 21
An operator $\wedge$ acts on two integers as follows: $4\wedge8=2412$, $5\wedge9=2812$, $1\wedge7=1618$, $2\wedge3=103$. Find $7\wedge8$.
Editorial assumption for a definite answer: use the source’s intended rule, concatenating the decimal forms of $2(a+b)$ and $3(b-a)$, in that order, without multiplying them. Examples alone do not uniquely define an operator.
Answer format: enter one whole number without units; leading zeros are optional. The source answer sheet uses four digits (for example, 7 is shaded as 0007).
Editorial assumption for a definite answer: use the source’s intended rule, concatenating the decimal forms of $2(a+b)$ and $3(b-a)$, in that order, without multiplying them. Examples alone do not uniquely define an operator.
Answer format: enter one whole number without units; leading zeros are optional. The source answer sheet uses four digits (for example, 7 is shaded as 0007).