Respuesta :

a) Yvonne has earned $4,960 by the end of the three years.
b) The interest rate was roughly 4.16%. (sorry, not sure how to show work for this one. I kinda just guessed)
c) If her interest rate was 1% greater, she would have an extra 775 dollars.
I apologize if this is wrong. You probably should double check, because I am a little rusty when it comes to math. Hope this helps, and I'm sorry if it didn't!
Photon
Hello,

a)  You have to know : Amount = Principal + interest

Therefore :

Amount : [tex]4000 + 960 = 4960[/tex]

b) You have to learn this by heart too , the formula for rate
 R = [tex] \frac{100*I}{PT} [/tex]

Therefore :

[tex]R= \frac{100*960}{4000*3} [/tex] 
[tex]R = 8[/tex]

The answer would be 8% per annum.

c) If the rate was 1% more, it would give R = 8 + 1 = 9% per annum.

Afterwards, the formula for Interest is : [tex]I = \frac{PRT}{100} [/tex]

Therefore : 

[tex]Interest = \frac{4000*9*3}{100} = 1080 [/tex] $

So in her account, if the interest was 1% greater, the amount in her account would have been :

$4000 + $1080 = $5080.

That gives $5080 - $4960 = $120 more dollars in her  account if the interest rate were 1% greater.

You won't need help in this exercice anymore ! :D

Hope this helps !

Photon