Guides/X is what % of Y
What percent is one number of another?
“42 is what percent of 70?” is the classic reverse of “what is 60% of 70?” You divide part by whole, then multiply by 100.
Formula
- Percent = (part ÷ whole) × 100
- 42 ÷ 70 = 0.6 → 60%
- Forward “percent of”:percentage of a number·find the whole.
Worked examples
- Quiz: 17 of 20 → (17/20)×100 = 85%.
- Budget: $250 of $2,000 rent share → 12.5%.
- Do not confuse with percent change from old to new —% increase·% decrease.
Common mistakes
- Swapping part and whole (70÷42…).
- Forgetting ×100 and reporting 0.6 as “0.6%”.
- Using percent-of language for percent-off sales —off vs of.