Factor Trio
Which of the numbers shown is the product of exactly 3 distinct prime factors?
Age
11 to 14
Challenge level
Problem
Which of the following numbers is the product of exactly $3$ distinct prime numbers?
$45$, $60$, $91$, $105$, $330$
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Student Solutions
Answer: $105$
$\begin{align}
45&= 3^2 \times 5\\
60 &= 2^2 \times 3 \times 5\\
91 &= 7 \times 13\\
105&=3 \times 5 \times 7\\
330 &= 2 \times 3 \times 5 \times 11
\end{align}$