3 teas and 2 coffees have a total cost of £7.80. 5 teas and 4 coffees have a total cost of £14.20. Work out the cost of one tea and the cost of one coffee.
Make x= Tea and y= CoffeeTherefore 3x + 2y = 7.80 (1) and 5x + 4y = 14.20. (2)Want either x or y to be equal for both equations- therefore make (1) 6x + 4y = 15.60 (3)“Same signs subtract” so do (3) - (2) ——> x = 1.40Then substitute x back into one of the equations, e.g 3(1.40) + 2y = 7.80And rearrange equation to find y. Therefore y= 1.80ANSWER: Tea = £1.40 and coffee = £1.80
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