An air conditioning salesperson receives a base salary of $2850 per month plus a commission. The commission is 2% of the sales up to and including $25,000 for the month and 5% of the sales over $25,000 for the month.

a. Write a piecewise function that relates the salesperson total monthly income based off or his/her sales for the month.
b. Determine the salesperson's monthly income if his/her sales were $43,000 for the month.