Graphical Solution to Word Problem involving Simultaneous Linear Equations
Graphical Solution to Word Problem involving Simultaneous Linear Equations
David bought 2 scones and 2 cups of coffee for $18. Ellie bought 3 scones and 2 cups of coffee for $22.
Find the cost of 1 scone and 1 cup of coffee.
Let the cost of a scone be $x and a cup of coffee b $y
We can write, for David's purchase : 2x + 2y =18
Ellie's purchase : 3x + 2y = 22
This problem is easily solved by algebra, by elimination of 2y and we get x = 4, and also y = 5
But for the purpose of learning the graphical method : We plot both equations above on the graph
The point of intersection of both straight line graphs lies at (x, y) = (4, 5)