how to solve t+4/3t=84?

Question

At the end of the day, a pharmacist counted and found she has 4/3 as many prescriptions for antibiotics as she did for tranquilizers. She had 84 prescriptions for the two types of drugs. How many prescriptions did she have for tranquilizers?

Answer 1

x+y=84

y=(4/3)x

x+(4/3)x=84

(7/3)x=84

x=(3/7)*84

x=36

y=48