## LaShai Group Title The sales tax on a new car varies directly to (or is directly proportional to) the price of the car. If $1,800 in sales tax is paid for a$25,000 car, what is the purchase price of a car worth $1,600 in sales tax? one year ago one year ago • This Question is Closed 1. geoffb Group Title You know that you pay$1800 on a $25000 car. What you need to know is the value of a car when you spend$1600 in tax. You can do this by cross-multiplying: $\frac{1800}{25000} = \frac{1600}{x}$

2. LaShai Group Title

okay

3. LaShai Group Title

So 1,800x=4,000,000

4. LaShai Group Title

And x = 2,222.22 Thank you!

5. geoffb Group Title

Close, but it's not 4 million.

6. geoffb Group Title

It's 40 million.

7. geoffb Group Title

But your technique is right. Good job.

8. LaShai Group Title

Thanks

9. geoffb Group Title

No problem. And it makes sense that the car in $$x$$ should be about the same cost as the first car, since the taxes paid are about the same, too.

10. LaShai Group Title

So its actually \$22,222.22

11. LaShai Group Title

And the same thing goes for this problem right? The time it takes to complete a project varies inversely (or is inversely proportional to) the number of people working on the project. If a project takes 6 hours to complete with 2 people, how many people are needed to complete the same project in 3 hours?

12. geoffb Group Title

Yes, it's the same idea.

13. LaShai Group Title

Okay thanks