another math calculation problem

Nursing Students Pre-Nursing

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Wondering if someone can walk me through this calculation problem.

Order:500 cc D5W with 20 mEq KCL

Avail: 15 mEq/7.5cc

How many cc of the KCl must be added to the IV bag?

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how about you try it first, show us the steps... and then we'll guide you.:)

hint: use the equation -

Desire dose

------------- X Supply

Have dose

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20 mEq/15 mEq *7.5 = 10

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I just keep trying to plug in the 500 cc into the equation

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Specializes in Long Term Care, Pediatrics.

It sounds like you are having a lot of trouble with your math, does your school offer free tutoring? I know many do, and we really won't be helping you learn if we do your math for you. We can't be there for your tests or boards. I know nursing school is really hard, but you can do it and I'm sure you'll make a great nurse. :) Good luck.

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Wondering if someone can walk me through this calculation problem.

Order:500 cc D5W with 20 mEq KCL

Avail: 15 mEq/7.5cc

How many cc of the KCl must be added to the IV bag?

The order asks for 20 mEq KCL to be added to the IV bag.

Formula method:

Desired / Have * Quantity = Amount Needed

Desired Amt = 20 mEq KCL, Have (what you have on hand) is 15 mEq. The Quantity of what you Have on hand is 7.5cc.

So 20mEq/15mEq x 7.5cc = 10 cc

Dimensional Analysis:

X cc = 7.5cc/15mEq * 20 mEq

X = 10 cc

Always make sure the units cancel out.

This is really straightforward problem. What are you having trouble with?

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Specializes in Long Term Care, Pediatrics.

Wondering if someone can walk me through this calculation problem.

Order:500 cc D5W with 20 mEq KCL

Avail: 15 mEq/7.5cc

How many cc of the KCl must be added to the IV bag?

Okay, I see now, this is a tricky question, in nursing, you have to learn to sort out information. State boards are full of tricky questions, in this case the 500 cc D5W is pretty much irrelevent. Look at what answer they are asking for "how much potassium must be added?" Looks like this question is asking you to assume that the D5W comes in bags of 500 cc in your hospital. Don't over think it.

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I just keep trying to plug in the 500 cc into the equation

Why?

If you have a 2,000 lb car that needs to go 100 miles and you get 20 miles to the gallon, how many gallons of gas do you need?

Of course you know the answer, but did you try to plug the car's weight into your calculations?

Practice these problems until you are blue in the face. When tested, you will very often be given extra information you don't need. Students who don't practice often try to plug extraneous numbers into the calculations.

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Thanks to all of you for your help. When I see numbers in a problem, I always try to plug them all in into an equation. I am learning what is relevant and what is not. Thanks once again:)

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20 mEq/15 mEq *7.5 = 10

bingo! good job :D you got it. When you look at the problem, don't over read it. Sometimes they throw in the #'s to confuse you. It was only asking for how many mEq KCL you should add to a 500cc bag. The pharmacy gave you its KCL supply... and what was the question asking for? the amt of KCL :yeah:

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Next time you get stuck on a problem, try Youtube.com. Crazy as it sounds, they have videos that show you step by step instruction or any math problem. (kids love it) Best of luck and Rock that Math class!

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