College

1. Write a linear equation [tex]y = mx + b[/tex] for each scenario by identifying the slope and y-intercept. Then use substitution to answer the second question about the equation.

a. Ted currently owns 10 Hot Wheels cars. He plans on buying 20 new cars every year.

i. Equation:

ii. How many Hot Wheels will Ted have in 13 years?

b. Todd can remove 15 square feet of weeds every minute, and he has 1,000 square feet of garden with weeds.

i. Equation:

ii. How many square feet of the yard will still be left to be mowed after 30 minutes?

Answer :

Sure! Let's solve each part of the problem step by step.

### Part a: Ted and Hot Wheels Cars

1. Identify the initial amount and rate of change:
- Ted currently owns 10 hot wheels cars. This is your starting point, or y-intercept (b).
- He plans to buy 20 new cars every year. This is the rate of change, or slope (m).

2. Write the equation:
- The equation of a line in the slope-intercept form is [tex]\( y = mx + b \)[/tex].
- For Ted's scenario, it becomes [tex]\( y = 20x + 10 \)[/tex].

3. Determine the number of hot wheels in 13 years:
- Substitute x with 13 in the equation:
[tex]\[
y = 20(13) + 10
\][/tex]
- Calculate:
[tex]\[
y = 260 + 10 = 270
\][/tex]

So, Ted will have 270 hot wheels cars in 13 years.

### Part b: Todd and Garden Weeds

1. Identify the initial situation and rate of change:
- Todd initially has 1,000 square feet of garden weeds. This is the starting point, or y-intercept (b).
- He removes 15 square feet of weeds every minute. Since the weeds are being taken away, this is a negative rate of change, or slope (-m).

2. Write the equation:
- The equation here reflects a decrease in weeds, [tex]\( y = -15x + 1000 \)[/tex].

3. Determine how many square feet of yard will still be left after 30 minutes:
- Substitute x with 30 in the equation:
[tex]\[
y = -15(30) + 1000
\][/tex]
- Calculate:
[tex]\[
y = -450 + 1000 = 550
\][/tex]

Therefore, 550 square feet of the garden will still have weeds after 30 minutes.

I hope this helps you understand the solution! Let me know if you have any questions.