Questions on Common Multiples
Multiple-choice questions on Common Multiples designed for 6th grade, each with five alternatives and answers explained at the end. The problems are based on hypothetical real-life situations to make learning more relatable and engaging.
Common Multiples - Multiple Choice Questions
1. Two buses stop every 15 minutes and 20 minutes respectively. If they both stopped at 8:00 AM, when will they stop at the same time again?
A) 8:15 AM
B) 8:30 AM
C) 9:00 AM
D) 8:45 AM
E) 9:15 AM
2. Julia goes to the gym every 6 days, and her friend Sara goes every 8 days. If they both went today, in how many days will they go together again?
A) 24
B) 30
C) 32
D) 40
E) 48
3. A bell rings every 12 seconds and another bell every 18 seconds. If both rang together at 2:00 PM, when will they ring together again?
A) After 36 seconds
B) After 48 seconds
C) After 60 seconds
D) After 54 seconds
E) After 72 seconds
4. Tom buys apples every 9 days, and oranges every 15 days. Today he bought both. In how many days will he buy both again?
A) 30
B) 45
C) 60
D) 75
E) 90
5. A gardener waters one section every 10 days and another every 25 days. If he watered both today, when will he water both again?
A) In 50 days
B) In 60 days
C) In 100 days
D) In 75 days
E) In 150 days
6. Two runners complete a lap in 20 and 30 minutes respectively. If they start together at 8:00 AM, when will they meet at the starting point again?
A) 8:40 AM
B) 8:50 AM
C) 9:00 AM
D) 9:10 AM
E) 8:30 AM
7. A traffic light turns red every 45 seconds, another every 60 seconds. How long until they turn red at the same time again?
A) 90 s
B) 120 s
C) 135 s
D) 180 s
E) 240 s
8. A teacher gives homework every 4 days, and surprise quizzes every 6 days. When will both happen on the same day again?
A) In 10 days
B) In 12 days
C) In 14 days
D) In 16 days
E) In 20 days
9. Anna trains every 14 days and Ben every 21 days. If they both trained today, in how many days will they train together again?
A) 28
B) 42
C) 49
D) 56
E) 63
10. A planet orbits the sun every 18 months, another every 30 months. After how many months will they align again?
A) 48
B) 54
C) 60
D) 72
E) 90
11. Two machines beep every 25 and 40 seconds respectively. If they beep together at 9:00 AM, when will they beep together again?
A) 9:01 AM
B) 9:01:30 AM
C) 9:02 AM
D) 9:02:30 AM
E) 9:03:20 AM
12. A book club meets every 12 days, and a movie club every 16 days. If both meet today, when is the next time both meet together?
A) 24 days
B) 36 days
C) 48 days
D) 60 days
E) 72 days
13. A printer makes black-and-white prints every 6 minutes and color prints every 9 minutes. When will it make both at the same time again?
A) 12 min
B) 18 min
C) 24 min
D) 30 min
E) 36 min
14. A car requires maintenance every 90 days, and its tires every 120 days. If both were done today, when will both need to be done again?
A) 150 days
B) 180 days
C) 210 days
D) 240 days
E) 270 days
15. A reminder app alerts every 8 minutes, and another every 14 minutes. After how many minutes will both alert at the same time?
A) 56
B) 72
C) 84
D) 96
E) 112
16. A boy visits his grandma every 7 days and his aunt every 9 days. If he visits both today, when will both visits happen on the same day again?
A) 56
B) 63
C) 72
D) 81
E) 84
17. A theme park rotates lights every 10 and 18 minutes respectively. After how many minutes do both lights rotate together again?
A) 28
B) 30
C) 36
D) 40
E) 45
18. An elevator pings every 5 minutes and an alarm test runs every 12 minutes. When will both occur at the same time again?
A) 20
B) 30
C) 36
D) 60
E) 72
19. A robot recharges every 24 hours and uploads data every 36 hours. When will both happen at the same time again?
A) 48
B) 60
C) 72
D) 84
E) 96
20. A bakery bakes bread every 16 minutes and pastries every 20 minutes. If they start at the same time, when will both be baked together again?
A) 64
B) 80
C) 100
D) 120
E) 160
- Questions on Prime Factorization
- Questions on Greatest Common Factor (GCF) - Using Lists & Factor Trees
- Questions on Equivalent Fractions
Answer Key with Explanations
1. C – LCM of 15 and 20 = 60 mins → 9:00 AM
2. A – LCM of 6 and 8 = 24
3. D – LCM of 12 and 18 = 36 seconds
4. B – LCM of 9 and 15 = 45
5. C – LCM of 10 and 25 = 50
6. C – LCM of 20 and 30 = 60 minutes → 9:00 AM
7. D – LCM of 45 and 60 = 180 seconds
8. B – LCM of 4 and 6 = 12
9. B – LCM of 14 and 21 = 42
10. C – LCM of 18 and 30 = 90
11. E – LCM of 25 and 40 = 200 seconds → 3 min 20 s = 9:03:20
12. C – LCM of 12 and 16 = 48
13. B – LCM of 6 and 9 = 18
14. B – LCM of 90 and 120 = 180
15. C – LCM of 8 and 14 = 56
16. B – LCM of 7 and 9 = 63
17. C – LCM of 10 and 18 = 90
18. D – LCM of 5 and 12 = 60
19. C – LCM of 24 and 36 = 72 hours
20. B – LCM of 16 and 20 = 80
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