## 00kirsten 4 years ago How much money would you have to invest to make $300 within 2 years if the interest rate was 4.5%? • This Question is Closed 1. INewton $x \times 1.045^2 \geq 300 \implies x \geq \frac{300}{1.045^2}$ 2. 00kirsten umm so whats the answer?? 3. INewton Umm, umm, umm... the answer is do your own homework, kiddo. 4. INewton Or read what I posted and work out the answer for yourself. 5. INewton Interest rate of 4.5% => value goes up by a factor of 1.045 each year. 6. 00kirsten but that is confusing, thats not what it shows me to do on my practice stuff 7. 00kirsten my practice stuff is like P = r x t stuff ... what you posted looks nothing like what im supposed to do, thats why i dont understand what u wrote 8. INewton If m money is invested, you have 1.045m after one year, and 1.045^2 m money after two years. if this equals 300, you have m = 300/1.045^2 = 287.08 to 2 decimal places. So if you want over 300, the mimnimum amount (to the nearest$) is 288. There.

9. INewton

Where 1.045^2 = 1.045 x 1.045

10. 00kirsten

isnt it supposed to look something like ... 300 x .045 x 2 = ??

11. INewton

Oh, you want 300 extra, not 300 in total? My mistake, sorry. It would be m * 0.045 * 0.045 = 300 m=300/0.045^2 = 300/(0.045 * 0.45)

12. 00kirsten

300/0.045 x 2 = ?? is that wat its supposed to be like

13. INewton

The last one was a typo, sorry again. They're both 0.045. But it's 0.045 TIMES ITSELF. Not x 2. Sorry, so many silly mistakes by me, I was a little too mean earlier.

14. INewton

300/(0.045 x 0.045)

15. 00kirsten

are you sure lol

16. INewton

I study Mathematics at the best University in the world. I am sure.

17. 00kirsten

and what university is that mr.newton

18. INewton

Cambridge, England.

19. 00kirsten

ohhh ic. My dads home england. So about that equation ... why did u do 0.045 twice??? im pretty sure i have to show the 2 in my equation

20. INewton

In the first year, it goes up by 4.5% , so you have 0.045 more. The second year, it goes up by it again, so you have ((1.045) x starting money) x 1.045) = starting money x 1.045 x 1.045 or 1.045^2. The extra money is 0.045 x 0.045 x starting money, and this is equal to 300.

21. INewton

Wait, one second. Sorry, it's about 4am here. You have 1.045 * 1.045 the starting money. If you want 300 extra, then 1.045^2 x starting money = starting money +300 So 300 = (1.045^2-1)m so m = 300/(1.045^2-1) = 300/((2.045)(0.045)). Wow, I am so sorry. What is wrong with me today. The answer is $3259.98 =$3260 3260 * 1.045 * 1.045 = 3560 = 3260 + 300. WOW, sorry, I have never looked at it for the profit not total, so made a silly mistake. Goodnight, And sorry again. fluttering hell, what's wrong with me today.

22. INewton

That is possibly the most embarrassingly bad maths I have done in my entire life.

23. 00kirsten

wat is * ?

24. INewton

Just another symbol for times, x, I use them interchangeably :(

25. 00kirsten

so he must invest 3259.98 to make $300 within 2 years if the interest rate was 4.5% ??? 26. INewton Yes, yes - 300/(1.045 x 1.045 - 1) = 300/(2.045 x 0.45) = 3259.98 3259.9837, to be exact, but$3260 is probably what you want. I am going, sorry for wasting your time (and mine, I am going to have about 3 hours sleep now :/) Have a nice life.

27. 00kirsten

ok thank you...