A few more nursing math problems

melmarie23, MSN, RN · May 18, 2009

1. order=0.2mg
dose on hand= 0.4mg/mL
0.2mg/xmL=0.4/mL
0.4x=0.2, solve for x
x=0.5mL
2. order= 2mg
dose on hand= 5mg/ml
2mg/xmL=5mg/mL
2=5x, solve for x
x=0.4ml
still working on 3 (I am doing these during commercials...watching Desperate Housewives)

deemarys · May 18, 2009

1. order=0.2mg
dose on hand= 0.4mg/mL
0.2mg/xmL-0.4/mL
0.4x=0.2, solve for x
x=0.5mL
2. order= 2mg
dose on hand= 5mg/ml
2mg/xmL=5mg/mL
2=5x, solve for x
x=0.4ml
still working on 3 (I am doing these during commercials...watching Desperate Housewives)
Which method are you using? I use S/H = x/D
Is that what you used?
Thanks for helping :)

deemarys · May 18, 2009

Think I got it.

1/0.4 = x/0.2 = 0.5

This is my method, don't know what its called.

deemarys · May 18, 2009

I think I am good now. Have a proficiency exam tomorrow. Got 100% last time, hopefully can pull it off again. Thanks for your help :)

beth66335, BSN, RN · May 18, 2009

1)the physician has ordered naloone hydrochloride 0.2 milligram iv from a vial labeled 0.4 milligram per milliliter. the nurse should administer_______________
0.4mg: 1ml :: 0.2mg : x ml
0.4x = 0.2 ( divide 0.2 by 0.4)
x=0.5
i tried this problem over and over and came up with 0.8. answer is really 0.5. where did i go wrong here....
2)the physician orders valium 2 milligrams im every 6 hours as needed to calm restlessness in a client. the on hand supply is valium 5 milligrams per milliliter. the nurse will administer_______________.
5mg : 1ml :: 2mg : x ml
5x = 2 ( divide 2 by 5)
x=0.4
the answer is 0.4 which is no where close to what i got for an answer.
3)the order is for neostigmine methylsulfate 2.25 millilters. im symptomatic control of myasthenia gravis. the supply is neostigmine methylsulfate 1:2000. the nurse will prepare an injection of _____________.
i'm not sure on this one since i don't know what units the ratio is...
the answer is 4.5ml. if you get this please show the steps.

i can help with 2 anyway...

JenRN30, BSN · May 18, 2009

A good formula to use is Desired/Have x Quantity

D

H x Q

1) 0.2 (desired or ordered)/0.4 (have or supply) = 0.5 x 1 mL (quantity)

This equals 0.5 mL

If there was 0.4 mg in 2 ml it would be 0.2/0.4 = 0.5 x 2 = 1 mL

Make sense?

2) 2mg/5mg = 0.4 x 1 mL = 0.4 mL

3) okay, I think this is the right way to do it, but not sure...

2000 ml in 1 g

So, 2000 ml in 1000 mg

2.25 mg (desired)

1000 mg (have) x 2000 ml (quantity) = 4.5 mL

Gosh, I hope that's right

melmarie23, MSN, RN · May 18, 2009

3. order= 2.25mL

dose on hand= 1:2000, (meaning 1mL= 2000mg)

xmg/2.25mL=2000mg/mL, solve for x

2.25(2000)=x

x=4500mg=4.5g

I dunno if that is what they meant by 4.5 in the answer you gave

melmarie23, MSN, RN · May 18, 2009

I use ratio and proportion. Its the only way that makes sense to me/way that I dont get confused.

melmarie23, MSN, RN · May 18, 2009

3) okay, I think this is the right way to do it, but not sure...
2000 ml in 1 g
So, 2000 ml in 1000 mg
2.25 mg (desired)
1000 mg (have) x 2000 ml (quantity) = 4.5 mL
Gosh, I hope that's right

yeah thats right. Ignore my previous answer. :-P

deemarys · May 18, 2009

3. order= 2.25mL
dose on hand= 1:2000, (meaning 1mL= 2000mg)
xmg/2.25mL=2000mg/mL, solve for x
2.25(2000)=x
x=4500mg=4.5g
I dunno if that is what they meant by 4.5 in the answer you gave

Answer sheet says 4.5ml

beth66335, BSN, RN · May 18, 2009

Answer sheet says 4.5ml

Yes that's right, here it is in R&P;

1000mg: 2000ml :: 2.25mg : x ml

1000x = 4500

x = 4.5ml