Things I Learned in School

Intrest Rate & Population Rate Formula

Intrest Rate Not Compounded
A = P (1 + r * t)
[P] = initial investment --- [r] = intrest rate --- [t] = number of years
A = 200 ( 1 + 0.06 * 3 )
A = 200 ( 1.18 )
A = $236

Compound Yearly
A = P ( 1 + r ) ^t
[P] = initial investment --- [r] = intrest rate --- [t] = number of years
A = 200 ( 1 + 0.06 )^3
A = 200 ( 1.06 )^3
A = $238.20

Compound Daily or Monthly or Quarterly
A = P ( 1 + r/n )^n*t
[P] = initial investment --- [r] = intrest rate --- [n] = compounds per year
[t] = number of years
A = 200 ( 1 + 0.06/365 )^365*3
A = $239.44

Continues Compound
A = Pe^r*t
[P] = initial investment --- [r] = intrest rate --- [t] = number of years
A = 200e^0.06*3
A = 200e^0.18
A = $239.44


Population Formula
n(t) = n * e^r*t
[n] = present population --- [r] = yearly growth --- [t] = number of years
n(t) = 57e^0.04*7
n(t) = 57e^0.28
n(7) = 75.4 milion