Question 30
MediumOriginal questionA school hall's seat numbers are all two-digit numbers. A seat wins a prize if its number is divisible by both 3 and 4. How many seats win a prize?
Show the answer and explanation
CorrectNot quiteAnswer C
Correct answer: C
Explanation
Divisible by both 3 and 4 means divisible by 12.
Two-digit multiples of 12: 12, 24, 36, 48, 60, 72, 84, 96.
That is 8 seats.
Worth noting
You need numbers divisible by 12, not numbers divisible by 3 or by 4. Starting the list at 24 misses 12 and gives 7.
- Concept
- Divisibility by two co-prime numbers together
- Typical timeTypical
- 50 s
- Your timeYours
- —
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