Math questions and weird answers

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I think my professor has posted some wrong answers to math questions. I'm pretty sure I've done them correctly. Would anyone take a stab at these two??

12.  Order:  amoxicillin/potassium clavulanate, 20 mg/kg/day, po Q 6hrs

Available:  amoxicillin/potassium clavulante, 150 mg per tablet

The patient weighs 166 pounds.

How many tablets will you administer per dose? _________

13.  Order:  ampicillin (Principen), 50 mg/ kg / day, po, Q6hrs

Available:  ampicillin (Principen), 250 mg per 5 mL

The patient weighs 88 pounds.

How many milliliters should the patient receive per dose? _________

How many milligrams should the patient receive per dose? _________

Why don't you start by showing us what you have done, as well as what your instructor gave as the answers.

I went back and redid them with a fresh brain and realized I missed the parts about q6hr and didn't divide my doses up! I got the correct answers this time and feel a lot better.

I was really worried for a bit because there is definitely a wrong answer on a simple conversion problem. It was convert 1/150 g to mg. Her answer was 0.4

3 minutes ago, anilea said:

I went back and redid them with a fresh brain and realized I missed the parts about q6hr and didn't divide my doses up! I got the correct answers this time and feel a lot better.

[...]

Excellent.  Don't hesitate to come here and ask questions.  If it is a math problem, please post what you have done as this helps us better help you.

6 minutes ago, anilea said:

[...]

I was really worried for a bit because there is definitely a wrong answer on a simple conversion problem. It was convert 1/150 g to mg. Her answer was 0.4

Possibly.  If she wrote the problem as 1/150 g, then yes, she formatted the information incorrectly.  It should have been written as gr [grain] 1/150.  This is a unit of measure in the  apothecary system.  In my experience, sublingual nitroglycerin is the only medication I remember being ordered using grains, and that was phased out years ago.

While I (designated using Roman numerals) gr equals 64.799 mg, in practice both 60 and 65 mg have been used interchangeably.  If you're interested in finding out if your instructor provided the wrong answer, convert gr 150 to mg using the 60 mg:gr I conversion factor.

Best wishes.

Specializes in Primary Care, Military.
On 9/7/2022 at 9:13 PM, chare said:

Excellent.  Don't hesitate to come here and ask questions.  If it is a math problem, please post what you have done as this helps us better help you.

Possibly.  If she wrote the problem as 1/150 g, then yes, she formatted the information incorrectly.  It should have been written as gr [grain] 1/150.  This is a unit of measure in the  apothecary system.  In my experience, sublingual nitroglycerin is the only medication I remember being ordered using grains, and that was phased out years ago.

While I (designated using Roman numerals) gr equals 64.799 mg, in practice both 60 and 65 mg have been used interchangeably.  If you're interested in finding out if your instructor provided the wrong answer, convert gr 150 to mg using the 60 mg:gr I conversion factor.

Best wishes.

I saw a question about the conversion of grains to milligrams on a dosage calculation test when in orientation for an ER position as an RN once and laughed. I'd been an RN for 5 years already at the time and never ran across it. It's been over 14 years now and I still have never run across the use of grains, even on the prescribing end. I still find it cute to come across it in the academic setting, though. 

Specializes in Private Duty Pediatrics.

Aspirin gr 10 = approximately 650mg. (Each aspirin pill is gr 5).

Nitroglycerin gr 1/150 = 0.4mg

I guess it's easier for me because I'm old school; I can remember these meds being ordered in grains. ?

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