Question

Mr Wallace took 600mg of medicine. This was 75% of the full dose. What was the full dose?

Answer 1

.25 x 600 = 150
150 + 600 = 750mg

Answer 2

Set up a proportion.

75% = 0.75

600/0.75 = x/1

Cross multiply:

0.75x = 600

Divide 0.75 to both sides:

x = 800

So the full does is 800mg.