Answer:
6 games and 3 rides
Step-by-step explanation:
Let the number of games Brianna played be x,
and the number of rides she went on be y.
Total cost for games= 1.25x
Total cost for rides= 3.75y
Since number of games is twice the number of rides,
x= 2y -----(1)
Total costs= cost of games +cost of rides
![18.75= 1.25x +3.75y](https://tex.z-dn.net/?f=18.75%3D%201.25x%20%2B3.75y)
Multiply the whole equation by 4 to remove the decimals:
![75= 5x +15y](https://tex.z-dn.net/?f=75%3D%205x%20%2B15y)
Simplify by dividing the whole equation by 5:
![15 = x + 3y](https://tex.z-dn.net/?f=15%20%3D%20x%20%2B%203y)
Label the equation:
x +3y= 15 -----(2)
Although we can solve these 2 equations by substitution, since the question requires us to graphically solve, we have to graph 2 linear lines.
I will choose 3 points to plot on the graph for each equation:
x= 2y -----(1)
![\begin{tabular}{|c|c|c|c|} \cline{1-4}x & 2(1) = 2&2(2) = 4&2(3) = 6\\ \cline{1-4}y & 1 &2&3\\ \cline{1-4}\end{tabular}](https://tex.z-dn.net/?f=%5Cbegin%7Btabular%7D%7B%7Cc%7Cc%7Cc%7Cc%7C%7D%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7Dx%20%26%202%281%29%20%3D%202%262%282%29%20%3D%204%262%283%29%20%3D%206%5C%5C%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7Dy%20%26%201%20%262%263%5C%5C%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7D%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%5Cend%7Btabular%7D)
x +3y= 15 -----(2)
x= -3y +15
![\begin{tabular}{|c|c|c|c|} \cline{1-4}x & -3(1)+15= 12& -3(2)+15= 9& -3(3)+15= 6\\ \cline{1-4}y & 1 &2&3\\ \cline{1-4}\end{tabular}](https://tex.z-dn.net/?f=%5Cbegin%7Btabular%7D%7B%7Cc%7Cc%7Cc%7Cc%7C%7D%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7Dx%20%26%20%20-3%281%29%2B15%3D%2012%26%20-3%282%29%2B15%3D%209%26%20-3%283%29%2B15%3D%206%5C%5C%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7Dy%20%26%201%20%262%263%5C%5C%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%20%5Ccline%7B1-4%7D%3C%2Fp%3E%3Cp%3E%3C%2Fp%3E%3Cp%3E%5Cend%7Btabular%7D)
Let's plot these points on a graph paper. Then, join them with a straight line for each straight line graph. Please see the attached picture for the graph.
From (1): y= ½x
From (2): 3y= 15 -x
y= 5 -⅓x
From the graph, the solution of the equation is (6,3). The solution is the point on the graph in which the 2 lines intersect.
x- coordinate: 6
y- coordinate: 3
Thus, Brianna played 6 games and went on 3 rides.