Percent and ratio solution practice problems

Dosage calculation practice for nursing students: solve unlimited new problems below with instant checking, or work through the 14 problems with answers further down.

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Formula to use

X% solution = X g per 100 mL = X × 10 mg/mL

1:Y solution = 1 g in Y mL = 1,000 ÷ Y mg/mL

Open the percent and ratio solution (mg/ml) calculator to check your own numbers step by step.

14 practice problems with answers

Solve each problem on paper first, then open the answer to compare every step.

How many grams of sodium chloride are in 1,000 mL of 0.9% sodium chloride?
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1. 0.9% = 0.9 g per 100 mL.
2. 1,000 mL × 0.9 g ÷ 100 mL = 9 g.
Answer: 9 g
Epinephrine 1:1,000. How many mg are in 1 mL?
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1. 1:1,000 means 1 g in 1,000 mL.
2. 1,000 mg ÷ 1,000 mL = 1 mg/mL.
Answer: 1 mg
How many mg of lidocaine are in 1 mL of a 1% solution?
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1. 1% = 1 g per 100 mL = 1000 mg per 100 mL.
2. 1000 mg ÷ 100 mL = 10 mg/mL.
Answer: 10 mg
How many grams of dextrose are in 250 mL of D5W?
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1. D5W is 5% dextrose: 5 g per 100 mL.
2. 250 mL × 5 g ÷ 100 mL = 12.5 g.
Answer: 12.5 g
How many grams of dextrose are in 1,000 mL of D5W?
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1. D5W is 5% dextrose: 5 g per 100 mL.
2. 1,000 mL × 5 g ÷ 100 mL = 50 g.
Answer: 50 g
How many grams of dextrose are in 500 mL of D5W?
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1. D5W is 5% dextrose: 5 g per 100 mL.
2. 500 mL × 5 g ÷ 100 mL = 25 g.
Answer: 25 g
How many mg of lidocaine are in 5 mL of a 1% solution?
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1. 1% = 1 g per 100 mL = 10 mg/mL.
2. 5 mL × 10 mg/mL = 50 mg.
Answer: 50 mg
Order: magnesium sulfate 1 g. Available: magnesium sulfate 50% (500 mg/mL). How many mL contain the dose?
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1. 50% = 50 g per 100 mL = 500 mg/mL.
2. 1 g = 1000 mg; 1000 mg ÷ 500 mg/mL = 2 mL.
Answer: 2 mL
How many mg of lidocaine are in 1 mL of a 2% solution?
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1. 2% = 2 g per 100 mL = 2000 mg per 100 mL.
2. 2000 mg ÷ 100 mL = 20 mg/mL.
Answer: 20 mg
Order: magnesium sulfate 4 g. Available: magnesium sulfate 50% (500 mg/mL). How many mL contain the dose?
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1. 50% = 50 g per 100 mL = 500 mg/mL.
2. 4 g = 4000 mg; 4000 mg ÷ 500 mg/mL = 8 mL.
Answer: 8 mL
Order: magnesium sulfate 2 g. Available: magnesium sulfate 50% (500 mg/mL). How many mL contain the dose?
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1. 50% = 50 g per 100 mL = 500 mg/mL.
2. 2 g = 2000 mg; 2000 mg ÷ 500 mg/mL = 4 mL.
Answer: 4 mL
Epinephrine 1:10,000 (0.1 mg/mL). How many mL contain 1 mg?
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1. 1:10,000 means 1 g in 10,000 mL = 0.1 mg/mL.
2. 1 mg ÷ 0.1 mg/mL = 10 mL.
Answer: 10 mL
How many mg of lidocaine are in 10 mL of a 1% solution?
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1. 1% = 1 g per 100 mL = 10 mg/mL.
2. 10 mL × 10 mg/mL = 100 mg.
Answer: 100 mg
How many mg of lidocaine are in 2 mL of a 1% solution?
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1. 1% = 1 g per 100 mL = 10 mg/mL.
2. 2 mL × 10 mg/mL = 20 mg.
Answer: 20 mg