1) Sally was making donuts at a restaurant. She can make 30 donuts from 8:15 to 9:00. a. if she starts making donuts at 7:35 how many can she get done before 8:15? Explain your reasoning b. Write an equation to represent how many donuts Sally has left to make if she started counting at 8:15-given she already made donuts from 7:35-8:15. Your equation should be in slope intercept form. Explain your reasoning.

Respuesta :

It is a question for linear equation

Let the number of donuts be y and the time be x

Since she can make 30 donuts from 8:15 to 9:00

We will find how many minutes from 8:15 to 9:00

There are 45 minutes from 8:15 to 9:00

Then the first point is (45, 30)

We need to find how many donuts she can make from 7:35 to 8:15

Since there are 25 minutes from 7:35 to 8:00

Since there are 15 minutes from 8:00 to 8:15, then

There are 25 + 15 = 40 minutes from 7:35 to 8:15

By using the proportional way we can find the number of donuts

[tex]\frac{30}{45}=\frac{x}{40}[/tex]

By using the cross multiplication

[tex]\begin{gathered} x\times45=30\times40 \\ 45x=1200 \end{gathered}[/tex]

Divide both sides by 45

[tex]\begin{gathered} \frac{45x}{45}=\frac{1200}{45} \\ x=26.66666 \end{gathered}[/tex]

Then she can finish 26 donuts before 8:15

b.

The form of the slope-intercept form is

[tex]y=mx+b[/tex]

m is the slope

b is the y-intercept (initial amount)

Since she will start counting from 8:15

Then the initial amount will be the 26 donuts

b = 26

The slope will be the ratio between the number of donuts and the time

[tex]\begin{gathered} m=\frac{30}{45} \\ m=\frac{2}{3} \end{gathered}[/tex]

The equation is

[tex]y=\frac{2}{3}x+26[/tex]