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Maria bakes cakes and sells them in bags.
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She uses this formula to work out how much to charge for one bag of cakes.
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The cost equals the number of cakes multiplied by 20 pence plus 15 pence for the bag.
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How much will a bag of 12 cakes cost in pounds?
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Olivia buys a bag of cakes for five pounds and 15 pence.
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Use the formula to calculate how many cakes are in the bag.
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This question has two parts.
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The first part asks us to calculate how much a bag of 12 cakes will cost in pounds.
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We know the number of cakes is 12.
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We need to multiply this by 20 pence.
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12 times 20 pence equals 240 pence.
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Then we need to add 15 pence for the cost of the bag.
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240 pence plus 15 pence is 255 pence.
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We’re asked to write the answer in pounds.
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We write 255 pence as two pounds 55.
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In the second part of the question, we’re told how much money Olivia has spent: five pounds and 15 pence.
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We’re asked to use the formula to calculate how many cakes are in the bag.
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We know that a bag costs 15 pence.
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So we could subtract this from the five pounds 15 and that will tell us how much money Maria spent on cakes.
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Five pounds 15 take away the 15 pence leaves us with five pounds to spend on cakes.
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We know that the cost is calculated by multiplying the number of cakes by 20 pence.
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So to find out how many cakes Maria bought with her five pounds, we need to divide five pounds by 20 pence.
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We know that five 20ps make one pound.
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So 25 20ps must make five pounds because 25 is five times greater than five.
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There are 25 cakes in the bag.