Question

An antibiotic is sold in 4.0 mL ampoules that contain 60.0 mg of drug (60.0 mg/ 4.0 mL). How many milliliters of the antibiotic should be withdrawn from the ampoule if 20 mg are to be administered to a patient?Use correct number of sig figs

0.75ml?

Answer 1

No, and you know that is wrong because 60mg/4.0 mL = 15 mg/mL and
15 mg/mL x 0.75 mL is not 20 mg.
(60 mg/4.0 mL) x ?mL = 20 mg.
?mL = 20 x 4/60 = ?
You are allowed 2 s.f.

Answer 2

1.3 ml

Answer 3

right