Suppose you invest $1,600 at an annual interest rate of 4.6% compounded continuously how much will you have in the account after 4 years

Total = Principal * e^(rate*years)
where "e" is the mathematical constant 2.71828182828459
Total = 1,600 * e(.046*4)
Total = 1,600 * 2.71828182828459^(.184)
Total = 1,600 * 1.2020158231
Total = 1,923.23

Source:
http://www.1728.org/rate2.htm

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.