a)
1 coffee = 2.49
1 sandwich = 3.99
1 cookie = 0.99
She buys 1 coffee, 2 sandwiches, and 1 cookie
2.49 + 3.99 + 3.99 + 0.99 = total
2.49 + 3.99 + 3.99 + 0.99 = 11.46
Total = £11.46
b)
Ffion pays with £20
20 - 11.46 = 8.54
Change = £8.54
hope this helps