The question can be written algebraically, as:(a) 3t + 2c = 7.80(b) 5t + 4c = 14.20To work out the individual costs, we need to make one of the sets of variables equal. We can do this by multiplying the equation (a), giving (c):(a) 6t + 4c = 15.60(c) 5t + 4c = 14.20We can then subtract (c) from (a), giving:t = 1.40T can then be substituted into the initial equation (a), to work out the value of c:(3 x 1.40) +2c = 7.804.20 +2c = 7.802c = 3.60c = 1.80Finally we can check these values by substituting into (b):(5 x 1.40) + (4 x 1.80) = 7 + 7.2 = 14.20Then make sure to show your answers clearly, with units:coffee is £1.80 per cup and tea is £1.40 per cup
