Question

If a patient is to take Tetracycline 100mg three pills a day for 30 days. How many pills will that patient need?

a
60
b
C
d
30
90
180

Answer 1

90 pills

Explanation:

Answer 2

90 pills

Explanation:

We can think of 1 day as = 3 pills

and 2 days as 3 + 3 pills [3 for both days]

and 3 days as 3 + 3 + 3 pills [3 for each day]

and...wait!! we don't need to be adding all of these days up, we can use multiplication (which is repeated addition)

On day 2, we have two values of 3 pills, or two times that we add 3 pills

this can also be expressed as 3 × 2, which is the same thing as 3 + 3

3 × 2 = 6

3 + 3 = 6

So, we can apply the same idea to 30 days, and multiply 30 by 3 (we have 3 pills 30 times)

3 pills per day × 30 days

3 × 30 = 90

So, the patient needs 90 pills