Pharmacy Question on the Optional side?

Insulin R U-100 (100u/ml), dispense 3 bottles (10ml), 20 units q day. How many days will respectively bottle last?

a. 40
b. 45
c. 50

Thanks for all the helpers and supporters

Answers:

100 unit per ml x 10 ml per bottle = 1000 units

1000 units divided by 20 units per light of day = 50 days

OR

__100 units__ = __20 units__
****1 ml*************** x********

20 x 1 = 20 divided by 100 = 0.2 ml per day
10 ml divided by 0.2 ml = 50 days

C is the answer.