Let
y ------> the amount earned
x ----> the number of hours worked
In this problem we have a direct variation
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form y=kx
where
k is the constant of proportionality
k=y/x
In this problem the value of k is hourly rate
so
we have
For y=$90 -------> x=5 hours
substitute
k=90/5
k=$18 per hour
substitute in the linear equation
y=18x
so
Part 1) What is the meaning of the 18 that appears in the table?
18 is the hourly rate ( amount earned by a one hour of work)
Part 2) Explain how Lin used this table to solve the problem.
using the table
For x=8 hours
the value of y=$144
Verify with the equation
y=18x
y=18(8)=144 -----> is ok
Part 3) At this rate, how much would Lin be paid for 3 hours of work? For 2.1 hours of work.
For x=3 hours
substitute in the equation
y=18x
substitute the value of x
y=18(3)=$54
For x=2.1 hours
y=18(2.1)=$37.8