Question

If the operation $\oplus$ is defined by $a\oplus b=a^2+b^2$ for all real numbers $a$ and $b$ then $\left(2\oplus 3\right)\oplus 4$ is equal to

• A. $120$
• B. $185$
• C. $175$
• D. $129$

Answer 1

The correct option is B

$185$

Explanation for correct option:

Given $a\oplus b=a^2+b^2$

$$\begin{gathered} \therefore 2\oplus 3=2^2+3^2 \\ =13 \\ \therefore \left(2\oplus 3\right)\oplus 4=13\oplus 4 \\ ={13}^2+4^2 \\ =185 \end{gathered}$$

Hence, option B is correct