In the first year of ownership, a new car can lose 20% of its value. If a car lost $4200 of value in the first year, how much di
2 answers:
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Answer:
40
Step-by-step explanation:
Two ways we can solve this problem:
1. Graphically
2. Mathematically
Because you already solved it graphically, I will show you how to do so mathematically. Of course, graphically is much much easier and more efficient in this problem.
Let's break the problem down.
First, we are given a graph which contains a slope.
To find slope, we use the technique -> rise/run
Picking 2 obvious points from the graph, we can see
1st point -> (10, 20)
2nd point -> (40, 80)
Now, let's find the slope
Now, we have an equation y = 2x, where y = number of pies and x = cups of sugar
We want to find how many cups of sugar we need to bake 80 pies. Simply substitute 80 = number of pies = y
y = 2x -> 80 = 2x
Solving for x, divide both sides by 2
40 = x
We need 40 cups of sugar.