To determine if each of the numbers (12, 19, 22, 28, 30) is a counterexample to the conjecture "any number divisible by 2 is also divisible by 4," we need to check the divisibility of each number by 2 and then by 4.
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12:
- Divisible by 2: Yes (12 ÷ 2 = 6)
- Divisible by 4: Yes (12 ÷ 4 = 3)
- Counterexample: No
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19:
- Divisible by 2: No (19 is odd)
- Counterexample: No (since it's not divisible by 2)
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22:
- Divisible by 2: Yes (22 ÷ 2 = 11)
- Divisible by 4: No (22 ÷ 4 = 5.5)
- Counterexample: Yes
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28:
- Divisible by 2: Yes (28 ÷ 2 = 14)
- Divisible by 4: Yes (28 ÷ 4 = 7)
- Counterexample: No
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30:
- Divisible by 2: Yes (30 ÷ 2 = 15)
- Divisible by 4: No (30 ÷ 4 = 7.5)
- Counterexample: Yes
To summarize:
- 12: No
- 19: No
- 22: Yes
- 28: No
- 30: Yes
So, for your question, the numbers that are counterexamples to the conjecture are 22 and 30, and the others (12, 19, 28) are not counterexamples.