Answer:
Part A
1. After 4 weeks of work, Jeremy has saved 300
2. Jeremy worked 8 weeks in order to save $600
3. For every one week of work, Jeremy saved 75 dollars
4. If Jeremy works 15 weeks, then he can expect to save 1,125 dollars
Part B
1. Saeed orders 15 meals and his total cost of delivery is $24
2. Saeed paid $32 to have 20 meals delivered
3. For every meal delivered, Saeed is charged $1.6
4. If Saeed pays $19.20 in delivery fees then he ordered 12 meals
Explanation:
Part A
The given graph gives the proportional relationship between total amount saved and the number of weeks worked
1. Reading from the graph, at the point where the vertical line from point 4 touches the line of the graph, an horizontal line to the vertical y-axis touches the y-axis at 300
Therefore;
After 4 weeks of work, Jeremy has saved 300
2. The point where an horizontal line from point 600 on the vertical y-axis touches the line of the graph, a vertical line drawn to the horizontal, x-axis touches the x-axis at 8
Therefore;
Jeremy worked 8 weeks in order to save $600.
3. The rate of change of the amount saved to the number of weeks worked, 'm', for the given proportional relationship (straight line relationship, passing through the origin) is given as follows;
Rate of change, m = Constant = y/x
∴ Rate of change of the amount saved to the number of weeks worked = (300-0)/(4 weeks- 0 week) = 75/week
Therefore;
For every one week of work, Jeremy saved 75 dollars
4. The amount Jeremy would have saved in 15 weeks, 'A', is given as follows;
A = m × n
Where;
m = The rate of change of the amount saved to the number of weeks worked = 75/week
n = The number of weeks worked
∴ A = 75/week × 15 = $1,125
Therefore;
If Jeremy works 15 weeks, then he can expect to save 1,125 dollars
Part B
From the graph, we have;
1. From the graph there is a proportional relationship between the total cost of delivery and the number of meals
At the point a vertical line drawn to the line of the graph from 15 on the horizontal axis (number of meals), a horizontal line drawn to the vertical y-axis touches the y-axis at 24
Therefore;
1. Saeed orders 15 meals and his total cost of delivery is $24
2. From the point where the horizontal line from 32 on the vertical axis touches the linear graph of the relationship between the total cost of delivery and the number of meals, a vertical line drawn down to the horizonal axis touches the horizontal x-axis at 20
Therefore;
Saeed paid $32 to have 20 meals delivered
3. The rate of change of the total cost of delivery to the number of meals, 'm', is given as follows;
m = y/x (for proportional relationships)
Taking any corresponding 'x' and y-values
m = 16/10 = 32/20 = 24/15 = 1.6 Dollars/meal
Therefore;
For every meal delivered, Saeed is charged $1.6
4. From m = y/x = 1.6
When y = $19.20
x = y/m = $19.20/($1.6/meal) = 12 meals
Therefore;
If Saeed pays $19.20 in delivery fees then he ordered 12 meals.