1) A population of genetically modified

mosquitos doubles every month passing

along a gene which imparts resistance to

malaria. If this population started out with

twenty insects how many are there after

ten months?

This is a linear equation or y=mx+c. Where y is the number of mosquitos at a particular month and x is the number of months. We know the initial population of the mosquitoes is c=20. They population doubles every month so this is the gradient, m=2. Therefore the equation for the growth of the mosquito population is:

y = 2x + 20.

So after x = 10 months the mosquito population will be,

y=2 (10) + 20 = 40.

There will be 40 mosquitoes after ten months.