Which of the following numbers are composite? 1, 8.4, 15, 13, 9/2, 24, 33.

Concept: A composite number is a positive integer greater than 1 that has more than two positive factors (i.e., it is not prime and is not equal to 1). Non-integer values (decimals, fractions) are never classified as composite.

Application: Check each number given in the question — 1, 8.4, 15, 13, 9/2, 24, 33 — against this definition:

• 15: factors are 1, 3, 5, 15 — more than two factors, so 15 is composite.

• 24: factors are 1, 2, 3, 4, 6, 8, 12, 24 — more than two factors, so 24 is composite.

• 33: factors are 1, 3, 11, 33 — more than two factors, so 33 is composite.

• 1: not greater than 1, so it is neither prime nor composite.

• 13: factors are only 1 and 13 — exactly two factors, so 13 is prime, not composite.

• 8.4: a decimal, not an integer, so it cannot be composite.

• 9/2 (= 4.5): not a whole number, so it cannot be composite.

Cross-check: Among the seven given numbers, exactly three integers have more than two factors — 15, 24, and 33 — confirming this set as the complete list of composites.