Answer: 3 packages of cups and 4 packages of napkins
Explanation:
Given : Number of people invited = 60
There are 24 cups in a package and 18 napkins in a package.
To find : The least number of packages of cups and napkins that can be bought if each party guest gets one cup and one napkin.
The least common multiple of 24 and 18=

[∵
]
And 72>60, so we can fix the minimum amount of each of cups and napkins to be 72.
Now, the least number of packages of cups needed to be bought =

The least number of packages of cups needed to be bought =

Hence, the the least number of packages of cups and napkins that can be bought if each party guest gets one cup and one napkin is 3 and 4 respectively.