Nora has s stickers. The number of stickers she has is 15 of the number Evan has. Farid has 9 fewer stickers than Evan.
- Find the total number of stickers the 3 children have in terms of s.
- If Nora has 8 stickers, how many stickers does Farid have?
Need a hint?
If Nora's stickers are 1 part, how many parts does Evan have? Then take away 9 for Farid.
Worked answer
- (a) Nora's stickers are 15 of Evan's, so Evan has 5 × s = 5s stickers.
- Farid has 9 fewer than Evan, so Farid has (5s − 9) stickers.
- Total = s + 5s + (5s − 9) = (11s − 9) stickers.
- (b) Evan has 5 × 8 = 40 stickers.
- Farid has 40 − 9 = 31 stickers.
Answer: 31 stickers
The mistake this question tests
Habit
Collecting like terms in algebra
Many pupils think Evan has s ÷ 5 stickers because they see 15, but Nora has the smaller amount, so Evan has 5 times as many as Nora.
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