Use the simple interest formula to find the missing value. Rates are annual rates. Assume 360 days per year and 30 days per month. p = $12,543, r = 9.5%, t = ?, i = $3574.76
a. t = 5 years
b. t = 4 years
c. t = 3 years
d. t = 2 years

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.