Lisa and Katie are playing a card game, and a total of 900 points has been scored. Lisa scored 400 more points than Katie. If you let l= the number of points that Lisa scored, and k= the number of points that Katie scored, then the problem can be represented by the system:

l+k=900 and l=k+400

Graph the system. How many points did each of them score?

1 answer

To solve the system of equations, we can substitute l=k+400 into the first equation:

(k+400) + k = 900
2k + 400 = 900
2k = 500
k = 250

Now, substitute k=250 into the equation l=k+400:

l = 250 + 400
l = 650

So, Lisa scored 650 points and Katie scored 250 points.

Graphically, the equations intersect at the point (650, 250) on the graph. Lisa's score is on the x-axis and Katie's score is on the y-axis.