Question

The value of $\left(4{\oplus }_{5}2\right){\oplus }_{5}3$ is

• A. $4$
• B. $2$
• C. $1$
• D. $0$

Answer 1

The correct option is A $4$

$a{\oplus }_{c}b=\left(ab\right)\mathrm{mod}c$

$\therefore 4{\oplus }_{5}2=(4\times 2)\mathrm{mod}5=8\mathrm{mod}5=3$

Now, $3{\oplus }_{5}3=(3\times 3)\mathrm{mod}5=9\mathrm{mod}5=4$

Hence, $\left(4{\oplus }_{5}2\right){\oplus }_{5}3=4$

Option $A$ is correct.