Answer:
£42.04
Step-by-step explanation:
To make 1 sandwich, she needs 1 bread roll and 2 cheese slices.
To make 100 sandwiches, she needs 100 bread rolls and 200 cheese slices.
1 pack of bread rolls has 15 rolls.
100/15 = 6.66...
She needs to buy at least 7 bags of bread rolls.
1 pack of cheese slices has 20 cheese slices.
200/20 = 10
10 bags of cheese slices will make 100 sandwiches.
To make more than 100 sandwiches, she needs to buy at least 11 bags of cheese slices.
11 * 20 = 220
To have twice as many cheese slices as bread rolls, she would have to buy at least 110 rolls.
We need to find the least multiple of 20 that is also a multiple of 15, and that is greater than 220.
20 = 2 * 2 * 5
15 = 3 * 5
LCM = 2 * 2 * 3 * 5 = 60
The LCM of 15 and 20 is 60, but that is less than 220, so we find multiples of 60 until the first one that is greater than 220.
60
60 * 2 = 120
60 * 3 = 180
60 * 4 = 240
She will buy 240 cheese slices and 120 bread rolls.
240 cheese slices / 20 per bag = 12 bags cheese slices
120 bread rolls / 15 per bag = 8 bags bread rolls
12 bags cheese slices * £2.23 = £26.76
8 bags bread rolls * £1.91 = £15.28
£26.76 + £15.28 = £42.04
