Answer:
Coffee cost: £ 2.50
Tea cost: £ 1.50
Explanation:
Let C represent coffee and T represent tea. We have equations
C + T = 4
C + 3T = 7
We time the first equation by -1 and solve the price of tea!
-C - T = -4
C + 3T = 7
2T = 3
T = £1.50
Now we put 1.50 back in the equation to solve for the cost of a coffee!
C + 1.50 = 4
C = £ 2.50
So, the cost of a coffee is £ 2.50, and the price of a tea is £ 1.50