## anonymous one year ago A motorcycle cost $12,000 when it was purchased. The value of a motorcycle decreases by 6% each year. Find the rate of decay each month and select the correct answer below. • This Question is Closed 1. anonymous @Michele_Laino @mathmate @phi 2. anonymous 1 year has 12 months so whats 6 divide by 12? 3. anonymous 1/2 4. anonymous each month it depreciates by 0.5% 5. anonymous I need one more:) 6. anonymous ok 7. anonymous You decide to put$175 in a savings account to save for a $3,000 down payment on a new car. If the account has an interest rate of 3% per year and is compounded monthly, how long does it take you to earn$3,000 without depositing any additional funds?

8. anonymous

Compound interest formula$A=P(1+\frac{ r }{ 100 })^n$$3000=175(1+0.3)^n$

9. anonymous

300=227.5^n

10. anonymous

no it doesnt work like this

11. anonymous

$17.14285714=1.03^n$

12. anonymous

16.64^n

13. anonymous

?

14. anonymous

log 17.14285714 = 1.23408320596 log 5 = 0.69897000433 1.23408320596/0.069897000433

15. anonymous

Thats not an answer choice 8.0111 years 96.1332 years 93.2914 years 94.8377 years

16. anonymous

plug in all the in answers to the compound interest formula and try out

17. anonymous

? What do you mean?

18. anonymous

175(1.03)^n replace n with all the 4 options, see which one works

19. mathmate

or you take log!

20. anonymous

i did

21. phi

interest rate of 3% per year and is compounded monthly, that means you work in months (not years) and the interest rate is 0.03/12 the equation you want to solve is 175(1+ 0.03/12)^n = 3000 175(1.0025)^n = 3000 1.0025^n= 17.142857

22. anonymous

dayum i forgot something...the interest is compounded monthly!

23. mathmate

1.0025^n=3000/175 n log(1.0025)=log(3000/175) solve for n.

24. anonymous

knew something was off

25. anonymous

Ok hold on:)

26. anonymous

For some reason I got C?? I think I did something wrong

27. phi

when you find n, it will be in months divide by 12 to get years

28. anonymous

Was I right?

29. phi

what do you get for log(3000/175) ?

30. anonymous

1.23408320603

31. phi

so you have n log(1.0025) = 1.23408320603 divide both sides by log(1.0025) n= 1.23408320603/log(1.0025) what do you get for n

32. anonymous

1.2310056918=n

33. anonymous

1138.05283703 i mean

34. phi

ok, and that is in months divide by 12 to get years

35. anonymous

94.8377...

36. phi

yes

37. anonymous

ok so going back to #1 i think sesal gave me the wrong answer??

38. anonymous

A motorcycle cost \$12,000 when it was purchased. The value of a motorcycle decreases by 6% each year. Find the rate of decay each month and select the correct answer below.

39. anonymous

I got -0.005143% as an swer and she got -0.5% so I dont even know

40. phi

if it has a rate of 6% per year, or in this case -6%, as a decimal is -0.06 on a monthly basis, divide by 12: -0.06/12 = -0.005 in percent: -0.5%

41. anonymous

Ok! Thanks :) I was just checking!

42. anonymous

Solve 3^(2x)=7^(x-1) I got -7.74293 ??

43. phi