Question

Alex and ben go to a cafe with some friends. Alex buys 4 cups of coffee and 3cups of tea. He pays a total of £6.95. Ben buys 5 cups of coffee and 2 cups of tea. He pays a total of £7.20 Work out the cost of each cup of coffee and the cost of each cup of tea

Answer 1

c - the cost of one cup of coffee
t - the cost of one cup of tea
1.          (4c + 3t=6.95)*2     -----> 8c+6t=13.90   (1)
             (5c + 2t =7.20) *(-3) ---->-15c-6t=-21.60  (2)

2. Add equation (1) and (2)
             -7c= - 7.70,   c=1.10  Cup of Coffee  £ 1.10
3. substitute 1.10 into the first equation
4c + 3t=6.95,     4*1.10 + 3t=6.95,  3t = 6.95-4.40 =2.55,  t=  £ 0.85 cup of tea