# Med math question

1. Hey all, I have a med math question. Im getting ready to return to an online program and am brushing up on my med math but for some reason this question stumped me. I need help setting it up.

You have 5000mg/ml of awesome sauce and need dilute to 3000mg/2.2mls using NS 0.9 as a dilutant if needed.

How would I set this calculation up to solve? Any help would be greatly appreciated!

Thanks!

Joined: Aug '18; Posts: 2

3. desire
_____
have

The part that throws me is the mls I need it to be. I have 5000mg/ml but need 3000mg in 2.2mls. Im not sure where to incorporate the mls. Somewhere im rusty on the set up!

Marie
5. Are you being asked to asked to administer 3000 mg, diluted to a total volume of 2.2 mL? If this is the case, then I would withdraw the 3000 mg, then dilute that with the appropriate volume of diluent to give me the final volume of 2.2 mL.

Or, are you being asked how much diluent you would add to your 5000 mg to dilute the concentration to an equivalent of 3000 mg/2.2 mL? If this is the case, you can use ratio|proportion to determine the total volume of the 5000 mg at the diluted concentration.

I'm curious, where did this ridiculous problem come from?

Best wishes with your continued education!
6. D
_ X2.2ml ? correct me if im wrong.
H
7. Quote from Kennynguyenlvn
D
_ X2.2ml ? correct me if im wrong.
H
What are you trying to solve for?

And if you show us what you've done it makes it much easier for us to help you.
8. 3000mg = 2.2ml... and you have total of 5000mg to dilute. Assuming the question its asking how ml will dilute whole 5000 ml from what was giving. 3000mg X 2.2 divide 5000 mg equal 1.32 ml to dilute 5000mg.
9. What you've done here is close to providing the volume for 5000 mg if the concentration per mL was the same as the concentration for the 3000 mg/2.2 mL. To calculate this volume using the ratio : proportion method you would set the problem up like this:

From here you can either cross multiply, cancel like values, and solve for x. Alternatively, you could invert the second component, cancel like values, multiply the numerators and denominators, and solve for x. Either way will provide the total volume for the 5000 mg, if the concentration was the same as the 3000 mg/2.2 mL.

What should you do next to determine the volume of diluent to add to the on hand 5000 mg/1 mL?
10. Think about setting this problem up in a simpler version:

If you have on hand your awesome sauce in a dose of 5000 mg/1 mL and you want to dilute it so that it's 2500 mg/1 mL how much normal saline would you have to add in order to get the new concentration?
11. Quote from Kennynguyenlvn
3000mg = 2.2ml... and you have total of 5000mg to dilute. Assuming the question its asking how ml will dilute whole 5000 ml from what was giving. 3000mg X 2.2 divide 5000 mg equal 1.32 ml to dilute 5000mg.
No. If you want 2.2 mL to contain 3000 mg how would that work when you use only 1.32 mL in 5000 mg.

3000 mg/2.2 mL = 5000 mg/x mL, cross multiply to get the value of x. You clearly need more than 2.2 mL to add to the 5000 mg in order for there to only be 3000 mg in 2.2 mL.

I agree with the previous poster who said this is a ridiculous problem though.