#1**+1 **

OK...we need to use this "formula"

a ) A(t) = P ( 1 + r)^(t)

Where

A(t) is a future amount

P is the beginning amount

r = interest rate expressed as a decimal

t = number of years invested

b) We want to solve this for t

800 = 500 ( 1 + .015)^t divide both sides by 500

800/ 500 = ( 1 + .015)^t take the log of both sides

log ( 800/500) = log ( 1.015)^t and we can write

log ( 800/ 500) = t * log(1.015) divide both sides by log (1.015)

og (800/500) / log (1.015) = t ≈ 31.5 years

CPhill Nov 1, 2018