Question

The binary operation $\oplus$ on $R$ is defined as $a\oplus b=ab+5$, then the value of $2\oplus (5\oplus 3).$

• A. $40$
• B. $30$
• C. $50$
• D. $45$

Answer 1

The correct option is D $45$

$2\oplus (5\oplus 3)$
$=2\oplus (5\times 3+5)$
$=2\oplus 20$
$=2\times 20+5$
$=45$