ACT · Pre-Algebra · Ratios, proportions, and percentages
Question act-q-00249
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The question
A class has boys and girls in the ratio 8:8. If there are 128 students in the class, how many are boys?
- 128
- 64
- 64
- 8
Show answer & worked solution
Answer: 64
Worked solution. The ratio means there are 16 parts in total, with 8 parts boys. Each part is 128 / 16 = 8. So boys = 8 × 8 = 64.
Why each wrong choice is wrong. Swapping boys and girls is the obvious trap. Another distractor is the size of one 'part', which would be the answer if the ratio were 1:15 instead of 8:8.
Test-day tactic. Convert ratios into total parts first, divide the total by parts to get one unit, then multiply.
About this question type
These items mirror the SAT's ratio and percent items closely. The ACT tends to dress them in slightly more textbook-like phrasing, but the underlying math is identical.
You will see a question shaped like this one on roughly every other official ACT form, typically at a moderate position in the section — solidly within the range that separates a 600-band student from a 700-band student. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.