In a part-whole percent question, “of these” points back to the total, or whole, counted as . Identify that whole, then type the stated percent of it into Desmos to find the part the question asks for. Put the whole after “of,” not the group left over.
Hints
- Hint 1
The whole is the group counted as . “Of these books” refers back to all the books sold. Which count should go after of?
- Hint 2
The part is the group you’re trying to count. Take the stated percent of the whole; don’t subtract it from , because that would count the books outside the group.
Step-by-step
Find the percent of the whole
Step 1Identify the whole and write the fiction count
The whole is all books sold, the group counted as . The fiction books are the part, so if is their count, the statement becomes . Use , not the percent left over for non-fiction books.
- Step 2
Calculate the fiction count
Type in Desmos, keeping the percent sign. Desmos returns , so the bookstore sold 150 fiction books last week. Choice D.