1. A laptop computer is purchased for $1500. Its value each year is about 80% of its value in the preceding year. Its value in dollars after t years is given by the exponential function

V(t) = 1500(0.8)^t.

A) After what amount of time will the computer's value be $900?

B) After what amount of time will the computer's value be half the original value?

Please show your work.

2. World population growth. In 2008, the world population was 6.7 billion and the exponential growth rate was 1.14% per year.

a) Find the exponential growth function.
b) Predict the world population in 2014.
c) When will the world population be 8.0 billion?

Please show your work.