AlgebraEasy–MediumClass size from a third plus helpers
Algebra practice question
A third of the pupils in a class went on a trip, along with 2 teachers, making 7 people in total. How many pupils are in the class?
Answer: 15
p/3 + 2 = 7 gives p/3 = 5, so p = 15.
Common wrong answers
- If you answered 5
- 5 is the number of pupils on the trip.
- If you answered 21
- 21 is 7 × 3, forgetting to subtract the teachers first.
- If you answered 27
- 27 is (7 + 2) × 3.
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