Notes
Applications GCF, LCM
1) Marc vacuums the rugs every 18 days, mows the grass every 12 days, and pays the bills every 15 days.
Today he did all three.
a) What is the earliest time he will have to do all three again at once?
b) What is the earliest time he will have to do two again at once?
2) A machine has three colored lights each of which flashes on for an instant at regular intervals. The
yellow one flashes 15 times per minute, the blue one flashes 6 times per minute and the red one flashes
on 12 times per minute. You watch the machine and see all three lights flash on simultaneously. How
much longer must you wait before three lights flash on again simultaneously?
3) Mary and Sandy are on the same swim team for the summer. The coach placed each team member on a
different training schedule. As a result, Mary will swim laps every other day and Sandy will swim laps
every three days. The schedule begins on the first day of summer, with both girls swimming laps. How
many times will Mary and Sandy swim laps on the same day during the first ten weeks of summer?
4) Lisa Marie and Jenni want to make pies. Lisa Marie likes strawberry pie and Jenni likes peach pie. A
quart of fruit contains either 15 strawberries or 6 peaches. When they finish shopping, they discover that
they had the same number of strawberries and peaches. What is the least number of fruit that Lisa Marie
can buy?
5) As the owner of Bryce’s Super Sports, Bryce purchases 245 white golf balls, 238 yellow golf balls, and 84
orange golf balls. He asked his stock boy, Chad, to divide them up into bags, so that each bag of balls had at
least one of each color in them, and that each bag had the same number of total balls, and that there were no
balls left over. What is the largest number of balls he can put into each bag?
©Dr Barbara Boschmans
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