Help need the answer ASAP

How can you tell when x and y are not directly proportional?

Joel wants to buy a new tablet computer fram a store having a 20% off sale on all tablets. the tablet he wants has an original cost of $190. he also wants to make sure he has enough money to pay the 5% sales tax. part one joel uses the incorect expression 0.95(190)(0.8) to calculate that the tablet will cost him a total of $144.40. describe his error and write the correct expression part two how much will joel pay for the tablet show your work if you answer this question correctly you will receive a prize of 99 points good luck

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin. how many doctors use brand x aspirin