Can someone help me figure this out?

Updated | Posted
by nadenka nadenka (New) New Nurse

Has 15 years experience.

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ABSNstudent91, CNA

170 Posts

On 6/16/2022 at 3:53 PM, nadenka said:

I stupidly did 2.5/100X2ml= 0.05 then couldn't figure out at all the last question. 

So it sounds like you already converted the 1/2 teaspoon into 2.5 ml. If I'm doing it correctly, I think there is some overthinking happening. You already know the order is for 2.5ml (aka 1/2 teaspoon). 

If the concentration is every 2 ml there is 100mg (or for every 1ml there is 50mg) then every 0.5ml is 25mg.. you can just add it up. 

I've never seen a med math equation like this though.. they should represent real-life scenarios. Not sure they were trying to make it easier or harder for you all.

Your equation should work if you flipped the concentration on the bottom around.



Has 15 years experience. 9 Posts

On 6/16/2022 at 3:27 PM, faithjohn said:

Just my take

1. How many ml's are there in 1 teaspoon? 5ml; in 1/2 teaspoon? 2.5mls

2. Always figure out what the ordered dose is. Then use the formula. 

the ordered dose is 2.5mls (1/2 tsp)

Formula = ordered dose/concentration (when reducing concentration to every 1ml)

100mg/2ml = 50mg/1ml

2.5ml/50mg = 0.05ml (in mls because were multiplying by 1ml )

If they want to know how many milligrams in 1/2 tsp (2.5mls)?

2.5ml x 50mg = 125mg

in .05mls? 

 .05ml x 50mg = 2.5mg

Anyone can feel free to correct me.

You were CORRECT! thank you 



3,503 Posts

@nadenka, two members provided you the answer.  However, if you have to work this type problem again, do you think you can do so?

Best wishes.

On 6/16/2022 at 9:31 AM, nadenka said:

Motrin drops are available in a concentration of 100mg/2ml. The physician ordered Motrin ½ teaspoon for a temperature >101. The dosage is safe. How many ml should the nurse administer? How many mg of Motrin in this amount?

Please help I can not figure this out to save my life. Thank you. 

You should have included your work here. I will do it but not explaining it.


(2.5mL) (100mg/2mL)= 125mg 

(125mg)(2mL/100mg)= 2.5mL