A canteen had some eggs. In the morning, 14 of the eggs were used to bake cakes. In the afternoon, 23 of the eggs left after the morning were used to make fried rice. At the end of the day, 20 eggs were left.
- How many eggs were left after the morning?
- How many eggs did the canteen have at first?
- How many eggs were used in the afternoon?
Need a hint?
Work backwards: the 20 eggs left are what remains after the afternoon. Find how many eggs were there before the afternoon first.
Worked answer
- (a) After the afternoon, 13 of the eggs left after the morning remain.
- (a) 20 is 13 of the eggs left after the morning, so those eggs = 20 × 3 = 60.
- (b) 60 eggs is 34 of the total, because 14 was used in the morning.
- (b) 14 of the total = 60 ÷ 3 = 20, so the total = 20 × 4 = 80 eggs.
- (c) Eggs used in the afternoon = 60 − 20 = 40 eggs.
Answer: 40 eggs
The mistake this question tests
Habit
Fraction of a remainder
Pupils treat the 20 eggs as the amount left after the morning, or they take 23 of the remainder as the amount left, not the amount used.
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