## LaShai 3 years ago 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? • This Question is Closed 1. geoffb 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

okay

3. LaShai

So 1,800x=4,000,000

4. LaShai

And x = 2,222.22 Thank you!

5. geoffb

Close, but it's not 4 million.

6. geoffb

It's 40 million.

7. geoffb

But your technique is right. Good job.

8. LaShai

Thanks

9. geoffb

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

So its actually \$22,222.22

11. LaShai

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

Yes, it's the same idea.

13. LaShai

Okay thanks