Selected Applications of Linear Equations
1. (Giving label to unknown) The bill for the repair of an automobile is $380. Included in this bill is a
charge of $275 for parts, and the remainder of the bill is for labor. The charge for labor is $35 per
hour. How many hours were spent in repairing the automobile?
2. (A mixture problem) Ticket sales for a spaghetti dinner total $1350. There are two kinds of tickets:
adult tickets and children’s tickets, and their price are $6 and $3, respectively. Suppose there are
totally 250 tickets sold. Find the number of children’s tickets sold.
3. (Using formula) The formula for the perimeter of a rectangle is as follow:
P = 2l + 2w
where P , l and w denote perimeter, length and width, respectively.
A rectangular stained glass window has a perimeter of 18 feet. The height of the window is 1.25
times its width. Find the width of the window.