Same pattern as Cookies — Mrs Hoon's chocolate and almond batch. New numbers, new
story. Try each one on paper, then check the working below — or watch it drawn out, the
same way the problem above is.
Question 1
Mr Lim baked some muffins to sell. 2/3 of them were blueberry muffins and the rest were raisin muffins. After selling 90 raisin muffins and 3/4 of the blueberry muffins, he had 1/4 of the muffins left. How many muffins did Mr Lim sell?
Mr Koh had a collection of stickers. 3/5 of them were animal stickers and the rest were cartoon stickers. After giving away 120 cartoon stickers and 2/3 of the animal stickers, he had 3/10 of the stickers left. How many stickers did Mr Koh give away?
A farmer collected some eggs. 5/8 of them were brown eggs and the rest were white eggs. After selling 60 white eggs and 4/5 of the brown eggs, she had 1/4 of the eggs left. How many eggs did the farmer sell?
Write the fraction of blueberry muffins left, as a fraction of all the muffins.1/4 × 2/3 = 1/6
The muffins left altogether are 1/4 of the total. Take away the blueberry share left to find the raisin share left.1/4 − 1/6 = 1/12
State the raisin muffins as a fraction of the whole, using the same denominator.1/3 = 4/12
Subtract the raisin fraction left from the raisin fraction to find the fraction sold — this equals the 90 raisin muffins sold.4/12 − 1/12 = 3/12 = 1/4, so 1/4 of total = 90
Find the total number of muffins baked.90 × 4 = 360
Find how many muffins were left, then subtract from the total to find how many were sold.1/4 × 360 = 90; 360 − 90 = 270
Mr Lim sold 270 muffins, out of 360 baked.
The pattern. Turn '3/4 of the blueberry muffins sold' into a fraction of ALL muffins (1/6 left), so it can be compared directly against the 1/4 left overall and against the raisin share — then the 90 lands on a known fraction of the whole.
Write the fraction of animal stickers left, as a fraction of the whole collection.1/3 × 3/5 = 1/5
The stickers left altogether are 3/10 of the whole. Take away the animal share left to find the cartoon share left.3/10 − 1/5 = 3/10 − 2/10 = 1/10
State the cartoon stickers as a fraction of the whole, using the same denominator.2/5 = 4/10
Subtract the cartoon fraction left from the cartoon fraction to find the fraction given away — this equals the 120 cartoon stickers.4/10 − 1/10 = 3/10, so 3/10 of total = 120
Find the total number of stickers in the collection.120 ÷ 3 × 10 = 400
Find how many stickers were left, then subtract from the total to find how many were given away.3/10 × 400 = 120; 400 − 120 = 280
Mr Koh gave away 280 stickers, out of 400 in his collection.
The pattern. Turn '2/3 of the animal stickers given away' into a fraction of the WHOLE collection (1/5 left), so it can be set against the 3/10 left overall and against the cartoon share — then the 120 lands on a known fraction of the whole.
Write the fraction of brown eggs left, as a fraction of all the eggs.1/5 × 5/8 = 1/8
The eggs left altogether are 1/4 of the total. Take away the brown share left to find the white share left.1/4 − 1/8 = 1/8
State the white eggs as a fraction of the whole, using the same denominator.3/8
Subtract the white fraction left from the white fraction to find the fraction sold — this equals the 60 white eggs sold.3/8 − 1/8 = 2/8 = 1/4, so 1/4 of total = 60
Find the total number of eggs collected.60 × 4 = 240
Find how many eggs were left, then subtract from the total to find how many were sold.1/4 × 240 = 60; 240 − 60 = 180
The farmer sold 180 eggs, out of 240 collected.
The pattern. Turn '4/5 of the brown eggs sold' into a fraction of ALL the eggs (1/8 left), so it can be compared directly against the 1/4 left overall and against the white share — then the 60 lands on a known fraction of the whole.