During the summer months, one ice cream truck visits Suprabha's neighborhood every 4 days and another
ice cream truck visits her neighborhood every 5 days. If both trucks visited today, when is the next
time both trucks will visit on the same day?
Truck
Days of Visits
1
4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44,...
2
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,...
Solution:
Both ice cream trucks will visit JSuprabha's neighborhood in 20 days and in 40 days.
However, the problem asks: when is the next time both trucks will visit on the same
day?, so the final answer is IN 20 DAYS.
In the problem above, we have found multiples of the numbers 4 and 5. We have also found the Least Common Multiple (LCM)
of 4 and 5, which is 20. The Least Common Multiple of a set of whole numbers is the smallest multiple
common to all whole numbers in the set.
To find the Least Common Multiple of two or more whole numbers, follow this procedure:
Make a list of multiples for each whole number.
Continue your list until at least two multiples are common to all lists.
Identify the common multiples.
The Least Common Multiple (LCM) is the smallest of these common multiples.
