Problem Set 13
Name:______________________
Rea, 20067
Solve at least 8 problems on a separate sheet of paper, with this sheet attached to the front as a cover sheet. Show all work in detail, and be prepared to explain what you did to the class. 1)
A toy manufacturer is going to produce a new toy car. Each one costs $3 to make, and the company will also have to spend $200 to set up the machinery to make them. a) What will it cost to produce the first 100 cars? The first n cars? b) The company sells the cars for $4 each. Thus the company takes in $400 y selling 100 cars. How much money does the company take in by selling n cars? c) How many cars does the company need to make and sell in order to make a profit?
2)
A cyclist rides 30 km at an average speed of 9 km/hr. At what rate must the cyclist cover the next 10 km in order to bring the overall average speed up to 10 km/hr?
3)
Write an equation for the line that goes through the point (1,5) and that has slope 2/3.
4)
The equation 5x – 8y = 20 expresses a linear relationship between x and y. The point (15,7) is either on the graph of this line, above it, or below it. Which? How do you know?
5)
On a number line, how far is each of the following numbers from zero? a) 45
b) 7
c) x
d) x + 2
e) 0
On a number line, how far is each of the following numbers from 5? f) 17
g) 4
h) x
i) x + 3
j) x – 1
6)
Find an equation for the line containing the points (3,0) and (0,4).
7)
Find an equation for the line that passes through the points (4.1, 3.2) and (2.3, 1.6).
8)
To graph linear equations such as 3x + 5y = 30, one can put the equation into slopeintercept form, but unless the slope is needed, it is easier to find the x and yintercepts and use them to sketch the graph. Find the axis intercepts of each of the following and use them to draw the given line. An equation ax + by = c is said to be in standard form. a) 20x + 50y = 100
b) 4x – 3y = 72
9)
Translate the sentence “the distance between x and 12 is 20” into an equation using algebraic symbols. What are the values of x being described?
10)
Verify that (0,4) is on the line 3x – 2y = 8. Find another point on this line. Use these points to calculate the slope of the line. Is there another way to find the slope of the line? Describe this method!