Susan makes a purchase of $175 and is charged 7.75% for sales tax. what is the total cost of the purchase if susan charges it on a credit card with a daily interest rate of 0.039% and pays the balance off at the end of 30 days?
a. $176.17
b. $186.70
c. $190.77
d. $200.26

The temperature of a chemical solution is originally 21 ? c . a chemist heats the solution at a constant rate, and the temperature of the solution 75 ? c after 1212 12 minutes of heating. the temperature, tt t , of the solution in ? c is a function of x , the heating time in minutes. write the function's formula.