Pls Help- Maths!!!

bekindtokittens · Aug 10, 2009

hi everyone please help me with this question, i just cant work it out!
you are caring for a patient who has been charted for erythromycin 800mgs. the stock strength avaliable is 125mg/5mls. the patient only tolerates 15mls of their dosage when you are administering it.
a) what percentage of their total prescribed dose have they tolerated?
so i have done 800/125 x 5 = 32mls
32-15mls = 17mls
not sure how to get the answer which is 47% ????
b) how many mgs is this?
thanks to everyone who help me!
:redbeatherachiee

first you want to find out how many mgs are in 15 mls, since that is what the patient took.

i like ratios.

125mg = x

5ml 15ml

then cross multiply and divide. 125 x 15= 1875 1875 / 5= 375

therefore x = 375mg.

now you need to figure out what percentage 375 mg is of 800 mg. i assign the percentage amount as x.

800(x) = 375

divide both sides by 800 to get x alone. 375 / 800 = 0.46875

you'd round, so 375 mg is 47% of 800 mg.

kgh31386, BSN, MSN, RN · Aug 10, 2009

That's a good explanation, or you could work it another way as well.

The order is 800 mg, and you know that 125mg are in 5ml

Set up your units and cancel out

800mg x 5ml = 32ml(total dose)

```````125mg

your patient tolerated 15ml of the 32ml ordered, 15 divided by 32(15/32) is 0.468 or 47%.

And the number of mg tolerated from 15 ml is

15ml x 125mg = 375mg

`1`````5ml

rachiee · Aug 10, 2009

:yeah:Thanks alot!

Now i look at it i feel stupid!

Ta Rachiee

kgh31386, BSN, MSN, RN · Aug 10, 2009

Haha nah you're not stupid at all, just write it out different ways. usually there's more than one right way to get it :typing