49 Problem solving: systems of two linear equations containing two unknowns
The sum of two numbers is 9. If one number is subtracted from the other, the result is 1. Find the numbers.
The perimeter of a rectangle is 170 meters. If the length of the rectangle is 15 meters more than the width, what are the dimensions of
the rectangle.
Jonathan and Samantha row their canoe 33 miles downstream in 3 hours. After a picnic, they row back upstream. After 4 hours they only
travel 20 miles. Assuming that they canoe at a constant rate and the rivers rate is constant, find the speed at which Jonathan and
Samantha can row in still water.
a worker invested $18,000 in two accounts, one yielding 5% interest and the other yielding 10%. If he received a total of $1300 in interest
at the end of the year, how much did he invest at 5%.
1.) let x = amount invested at 5%
2.) let y = amount invested at 10%
Suppose that Kristen placed and order for two burgers and five sodas, for a total of 1639 calories. Jake placed an order for five
hamburgers and three sodas, for a total of 2055 calories. How many calories are in a hamburger? How many calories are in a soda?
1.) let x = the number of calories in a hamburger
2.) let y = the number of calories in a soda
A wood craftsman makes children's desks for $75 each. His monthly fixed costs of operating the business are $3500. Each desk costs
$25 in material.
Find the revenue function R treating the number of desks x as an independent variable.
R(x) = 75x
Find the cost function C treating the number of desks x an an independent variable.
C(x) = 25x + 3500