两个数的最大公因数是 18。
两个数的最小公倍数是 324。
这两个数都大于 20。 求这两个数。 答案 ... 和 ...

1. Express the two numbers using their HCF

Let the two numbers be $18a$ and $18b$, where $a$ and $b$ are coprime.

Since the LCM is $324$,
$18ab=324$
$ab=18$

2. Find the coprime factor pair and calculate the numbers

The factor pairs of $18$ are
$(1,18),\ (2,9),\ (3,6).$

The pair must be coprime and both numbers must be greater than $20$.

$(2,9)$ is coprime, so the two numbers are
$18\times 2=36,$
$18\times 9=162.$