A survey indicated that 3 out of 5 doctors use brand X aspirin. If 2000 doctors were surveyed, how many used brand X?

For the answer to the question above,

The ratio is 2:3

2/5 = part of doctors that do not use brand x aspirin.

3/5 = part of doctors that use brand x aspirin.

2000 = total number of doctors surveyed.

so ...

Number of doctors that use brand x aspirin:

3/5 * 2000

= 1200 doctors

Number of doctors that do not use brand x aspirin:

2/5 * 2000

= 800 doctors

So the answer is 1200 doctors.