Least Common Multiple Word Problem

Melanie and Martin are both building a toy train track out of connecting pieces. Melanie has pieces that are 8 inches long while Martin's pieces are 20 inches long.  How long will the shortest track be that they can each build with the same length?

• 2
• 40
• 4
• 20

Two neon signs are turned on at the same time. Both signs blink as they are turned on. One sign blinks every 9 seconds. The other sign blinks every 15 seconds. In how many seconds will they blink together again?

• 48 seconds
• 45 seconds
• 16 seconds
• 8 seconds

The school cafeteria serves tacos every sixth day and cheeseburgers every eight day. If tacos and cheeseburgers are both on today’s menu, how many days will it be before they are both on the menu again?

• 14 days
• 24 days
• 34 days
• 44 days

Two clocks are turned on at the same time. One clock chimes every 15 minutes. The other clock chimes every 25 minutes. In how many minutes will they chime together?

• 55 minutes
• 25 minutes
• 60 minutes
• 75 minutes

Henry and Margo both began traveling around a circular track. Henry is riding his bike, and Margo is walking. It takes Henry 7 minutes to make it all the way around, and Margo takes 12 minutes. How much time will pass until they meet at the starting line?

• 84 minutes
• 48 minutes
• 854 minutes
• 78 minutes

Jenny goes to  karate class every 12 days.and too the library every 18 days. On December 1st she went to both class and the library. On what date will she do both class and go to the library?

• 24 days
• 36 days
• 42 days
• 52 days

Boxes that are 12 inches tall are being stacked next to boxes that are 18 inches tall. What is the shortest height at which the two stacks will be the same height?

• 24
• 18
• 36
• 72

If Juanita runs every third day and swims every fifth day, what is the first day that she will both run and swim again? 

• 5
• 15
• 45
• 30

Cups are sold 5 to a package and plates are sold 10 to a package. If you want to have the same number of each item for a party, what is the least number of packages of each you need to buy?

• 30
• 20
• 50
• 10

Avery gets newsletters by e-mail. He gets one for sports every 5 days, one for model railroads every 10 days, and one for music every 8 days. If he got all three today, how many more days will it be until he gets all three newsletters on the same day again? 

• 80 days
• 40 days
• 50 days
• 60 days