What is 50% of 42?

• A. 42
• B. 21
• C. 7
• D. 14

Answer: (B)

Finding a percent of a number means multiplying the number by that percent written as a decimal. Fifty percent equals 0.50, which is the same as one-half. So 42 × 0.50 = 21. Another way to see it is to take half of 42, which is 21. Quick check: half of 42 is indeed 21. The other options correspond to other fractions of 42 (such as a whole, a third, or a sixth), not 50%.