Some time in the future a human colony is started on Mars. The colony begins with 20000 people and grows exponentially to 100000 in 100 years.

Give a formula for the size of the human population on Mars as a function of $t=$ time (in years) since the founding of the original colony

Assuming the population continues to grow exponentially, how long will it take to reach a size of 260000?
years

What is the rate of change of the size of the population (measured in people per year) 350 years after the founding of the original colony?
people/year