Suppose that a new employee starts working at $7.17 per hour and receives a 3% raise each year. After time t, in years, his hourly wage is given by the equation y=$7.17(1.03)^to. Find the amount of time after which he wi l be earning $10.00 per hour. After what amount of time will the employee be earning $10.00 per hour?

Respuesta :

Answer:

12 years

Step-by-step explanation:

Exponential Growing

Some variables tend to grow in time following an exponential function. The general equation for y as a function of t is

[tex]y=b.r^{at}[/tex]

The case given in the question corresponds to the following function

[tex]\displaystyle y=7.17(1.03)^t[/tex]

We want to know the amount of time after which the function will be 10, or

[tex]\displaystyle 7.17(1.03)^t=10[/tex]

Rearranging

[tex]\displaystyle 1.03^t=\frac{10}{7.17}[/tex]

Solving for t

[tex]\displaystyle Ln1.03^t=Ln(\frac{10}{7.17})[/tex]

[tex]\displaystyle t.Ln1.03=Ln(\frac{10}{7.17})[/tex]

[tex]\displaystyle t=\frac{Ln(\frac{10}{7.17})}{Ln\ 1.03}[/tex]

[tex]\displaystyle \frac{0,3327}{0,02959}[/tex]

[tex]\displaystyle t=11.26\ years[/tex]

When t=11 years, the employee is not paid at $10 per hour yet. We must jump to the next integer value.

[tex]t=12\ years[/tex]