since, average of doctors using brand x aspirin is 3 out of 5
if we consider one part then one part will be equal to 3/5
total survey consists of 2000 doctors then to find the brand x aspirin we can use the unitary method that is multiply the total number by one part
2000 x 3/5= 400 x 3
= 1200
so, total 1200 doctors are using brand x aspirin
