A school organized a field trip for 100 students and 10 chaperones. Each student was given a snack pack containing items equal to 15% of the total number of students. Each chaperone received a snack pack with items equal to 25% of the total number of students. How many snack items were distributed in total?

Correct — A. Both packs are sized from the 100 students, not from everyone on the trip.

Student pack = 15% × 100 = 15 items
Multiply by 100 students: 100 × 15 = 1,500

Chaperone pack = 25% × 100 = 25 items
Multiply by 10 chaperones: 10 × 25 = 250

Add the groups: 1,500 + 250 = 1,750 → option (a)

Why the others are wrong

• (b)
  2000 — 2,000 − 1,500 = 500 would mean 50 items for each of the 10 chaperones. That is 50% of the students, not 25%.
• (c)
  2250 — It leaves 750 items for the 10 chaperones, 75 each. Their pack is 25% of 100 students, only 25 items.
• (d)
  2500 — It needs 100 items per chaperone after the students' 1,500, which is 100% of the students rather than the stated 25%.

A percentage is always of something, and the stem names it: "of the total number of students". That base is 100 for both groups, so the chaperones' pack is not built from 110 people.

Once the items per person are fixed, the total is a weighted sum: people in each group × items each, added across the groups.

Key facts

• 15% of 100 = 15 and 25% of 100 = 25.
• Total items = (group size × items per person), added over all groups.
• The base of a percentage is the quantity after "of".

Common traps

• Taking 110, students plus chaperones, as the base: 15% of 110 is 16.5, not a whole number of items.
• Giving the chaperones the students' 15% as well: that totals 1,650, which is not an option.

No directly related past PYQ was found.