Question

Photo attached: please see image for question.

Answer 1

A)

`p = 13000( {.865}^(t) )`

B)

`13000( {.865}^(t) ) = 7930`

`{.865}^(t) = .61`

`t * ln(.865) = ln(.61)`

`t = ( ln(.61) )/( ln(.865) ) = 3.41 \: years`