Question

If $j$ is chosen at random from the set $\{4,5,6\}$ and $k$ is chosen at random from the set $\{10,11,12\}$, what is the probability that the product of $j$ and $k$ is divisible by $5$ ?

• A. $\frac{2}{3}$
• B. $\frac{4}{9}$
• C. $\frac{7}{9}$
• D. $\frac{5}{9}$

Answer 1

The correct option is D $\frac{5}{9}$

The answer is $5/9$ Just form the "multiplication table" for $j$ and $k$.

The possible products are $40,50,60,44,55,66,48,60,72$.

Out of the 9 products, 5 are divisible by $5$.

Hence the probability that the product of $j$ and $k$ divisible by 5 is $5/9=0.5555$.