If you invest $3,900 at a 7.83% simple annual interest rate, approximately how long will it take for you to have a total of $10,000? a. 12 years b. 15 years c. 20 years d. 30 years

Apply simple interest formula
future value = present value (1+n*rate)
n=number of years
rate = annual interest rate in decimal

Plug in values,
10000=3900(1+0.0783*t)
1+0.0783t=10000/3900
t=(10000/3900-1)/0.0783
=19.98 years.

With compound interest,  future value=present value (1+rate/n)^(nt)
n=1,rate=0.0783, future value=10000, present value=3900,
t=log(10000/3900)/log(1.0783)=12.49 years.

paul's with a y-intercept of $ 2856

8.4 10.4 8.9 10.9 have a good day