Question

In a café, I order a cup of tea and a piece of cake and it costs £1.10. The next time I order 2 cups of tea and one piece of cake and it costs £1.70. Find the cost of a piece of cake.​

Answer 1

Answer: piece of cake is 0.5£

Step-by-step explanation:

Tea + cake = 1.10
2 Tea + cake = 1.70

From that we can find the value of a cup of tea by simply 1.70 - 1.10 = 0.6£

If cup of tea = 0.6£

Then a cake = 1.10 - 0.6 = 0.5 £

Answer 2

£0.50

Step-by-step explanation:

t = one cup of tea

c = one piece of cake

t + c = £1.10

2t + c = £1.70

the cost increases by £0.60 (£1.70 - £1.10) when you order one more cup of tea which means that one cup of tea costs £0.60

substitute £0.60 into t + c = £1.10

£0.60 + c = £1.10

rearrange to get c = £1.10 - £0.60 = £0.50

so one piece of cake costs £0.50