Step 1: Start with the fraction 42/15.

Step 2: To convert a fraction into a percentage, divide the numerator by the denominator.

42 ÷ 15 = 2.8

Step 3: Multiply the result by 100 to get the percentage.

2.8 × 100 = 280.0%

Final Answer: 42/15 as a percentage is 280.0%.