SOLUTION: 17. The bill for 6 cups of coffee and 7 cups of tea is $5.90 while the bill for 18 cups of coffee and 5 cups of tea is $9.70.Find the total bill for 7 cups of coffee and 6 cups of

Algebra ->  Customizable Word Problem Solvers  -> Evaluation -> SOLUTION: 17. The bill for 6 cups of coffee and 7 cups of tea is $5.90 while the bill for 18 cups of coffee and 5 cups of tea is $9.70.Find the total bill for 7 cups of coffee and 6 cups of       Log On

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Question 393247: 17. The bill for 6 cups of coffee and 7 cups of tea is $5.90 while the bill for 18 cups of coffee and 5 cups of tea is $9.70.Find the total bill for 7 cups of coffee and 6 cups of tea?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Let x and y represent  the cost/cup for coffee and tea respectively

 6x + 7y = $5.90

18x + 5y = $9.70



-18x -21y = 5.90*-3

18x  + 5y = 9.70

      -16y = -8

         y = .50, cost/cup for tea

6x + 7y = 5.90

6x + 3.50 = 5.90

       6x = 2.40

        x = .40, cost/cup for coffee

total bill for 7 cups of coffee and 6 cups of tea?

  7*.40 + 6*.50 = $5.80