Use effective reasoning to determine the composite number described.I am a composite number. I am greater than 16, but less than 20. Two of my factors are a number and the number doubled. I am the number
The number that is greater than 16 but less than 20 is 18.
To verify if it is a composite number, we need to find two factors of 18 where one of the factors is the number itself and the other factor is the number doubled.
Let's check:
- If we take 18 as the number, its double is 36.
- Another factor of 18 should be a number between 18 and 36.
We notice that 18 is divisible by 3 since the sum of its digits (1 + 8 = 9) is divisible by 3. Testing further, we divide 18 by 3, which gives us 6.
Therefore, the two factors of 18 are 3 and 6 (where 6 is the number doubled). Thus, 18 is indeed a composite number.