A sandwich and a cup of tea cost £2.10. Two sandwiches and a cup of tea cost £3.70.
Calculate the cost of a cup of tea. Show your working.
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Let's make sandwich "s" and tea "t."

Make an equation with the variables.

a. 1s + 1t = 2.10

b. 2s +1t = 3.70

Then, do 3.70-2.10, to find the cost of a sandwich. It equals 1.60.

Then, do 2.10-1.60 to find the cost of a cup of tea, which is 0.50.

SO: The cost of a cup of tea is £0.50.

The cost of a sandwich is £2.10.

Hope this helps!