Here is the step-by-step solution to all 8 medication calculation problems from your worksheet.
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General Formula for Volume Calculations (Proportion Method):
>
Volume to Administer = (Ordered Dose / Available Dose) × Volume of Available Dose
Or in formula form:
>
V = (D_order / D_stock) × V_stock
Where:
- V = volume to administer
- D_order = dose ordered by provider
- D_stock = concentration available (dose per volume)
- V_stock = volume that contains the stock concentration
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Problem 1:
What volume is required for an injection if 750mg are ordered and stock ampules contain 200mg/ml?
- Ordered: 750 mg
- Stock: 200 mg/mL
→ V = (750 mg / 200 mg/mL) =
3.75 mL
✔ Answer: 3.75 mL
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Problem 2:
A dose of 3500mg of medication has been ordered. The medication comes in 5g/2mL. What volume will you give?
First, convert grams to milligrams:
- 5 g = 5000 mg → So stock is 5000 mg / 2 mL
→ V = (3500 mg / 5000 mg) × 2 mL
= (0.7) × 2 mL =
1.4 mL
✔ Answer: 1.4 mL
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Problem 3:
A flask of 1L of 4% dextrose in saline is required over 6hrs with a DF of 15. How many DPM is this?
- DF = Drop Factor = 15 drops/mL
- Total volume = 1 L = 1000 mL
- Time = 6 hours = 6 × 60 = 360 minutes
Formula for Drops Per Minute (DPM):
>
DPM = (Total Volume in mL × Drop Factor) / Time in Minutes
→ DPM = (1000 mL × 15) / 360 min
= 15,000 / 360 ≈
41.67 drops/min
(Round to nearest whole number as per clinical practice)
✔ Answer: 42 DPM
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Problem 4:
A dose of 4500mg of medication has been ordered. The medication comes in 5g/0.3mL. What volume will you give?
Convert 5g to mg: 5g = 5000 mg → Stock = 5000 mg / 0.3 mL
→ V = (4500 mg / 5000 mg) × 0.3 mL
= (0.9) × 0.3 mL =
0.27 mL
✔ Answer: 0.27 mL
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Problem 5:
What volume is required for an injection if 500mg are ordered and stock ampules contain 250mg/mL?
→ V = (500 mg / 250 mg/mL) =
2 mL
✔ Answer: 2 mL
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Problem 6:
What volume is required for an injection if 600mg are ordered and stock ampules contain 350mg/mL?
→ V = (600 mg / 350 mg/mL) ≈
1.714 mL
(Rounded to 2 decimal places for clinical use)
✔ Answer: 1.71 mL
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Problem 7:
A dose of 2g of medication has been ordered. The medication comes in 4g/0.4mL. What volume will you give?
→ V = (2g / 4g) × 0.4 mL
= (0.5) × 0.4 mL =
0.2 mL
✔ Answer: 0.2 mL
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Problem 8:
A flask of 1.5L of 0.9% saline is required over 8hrs with a DF of 20. How many DPM is this?
- Volume = 1.5 L = 1500 mL
- Time = 8 hrs = 8 × 60 = 480 min
- DF = 20 drops/mL
→ DPM = (1500 mL × 20) / 480 min
= 30,000 / 480 =
62.5 drops/min
(Round to nearest whole number)
✔ Answer: 63 DPM
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✔ Final Answers Summary:
1.
3.75 mL
2.
1.4 mL
3.
42 DPM
4.
0.27 mL
5.
2 mL
6.
1.71 mL
7.
0.2 mL
8.
63 DPM
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Let me know if you’d like these explained further or need help setting up the formulas!
Parent Tip: Review the logic above to help your child master the concept of paramedic med math worksheet.
