Rate of interest is 6 %
<em><u>Solution:</u></em>
Given in question that,
simple interest = $ 3240
number of years = 9 years
principal sum = $ 6000
To find: interest rate
<em><u>The simple interest is given as:</u></em>

Where, "p" is the principal
"r" is the rate of interest
"n" is the number of years
<em><u>Substituting the values in above formula,</u></em>

Thus rate of interest is 6 %
If you take the amount of green markers and divide them by the total, you come up with 0.21
If you do likewise with the others, you respectively come up with 0.47 and 0.32.
Graph b would be my guess!
D. -2/3 because when you do (y2-y1)/(x2-x1) you get -4/6 which simplifies to -2/3
D. -2, if the lines are parallel then the slope is the same but the y-int is different