Module 3: Calculating Medication Dosages - Practice Problems
Answers Using Ratio-Proportion
Problem
1.
Order = gr 3/4
Available = 30 mg tablets
Give___________
2.
Order = 100 mg
Available = 125 mg/5 mL
Give___________
3.
Order = 50 mg
Available = 80 mg/2 mL
Give___________
4.
Order = 0.5 g
Available = 250 mg capsules
Give___________
5.
Order = 0.24 g
Available = 80 mg per 7.5 mL
Give___________
6.
Order = 20 mg
Available = 10 mg per 15 mL
Give___________
Linear Ratio-Proportion
Cross-Multiplying RatioProportion
Cross-Multiplying
Ratio-Proportion
30 mg = 1 tab : 45 mg = x tab
30 x = 45
x = 1.5
Give 1.5 tablets
30mg 45mg

1tab
xtab
30mg 1tab

45mg xtab
30 x = 45
x = 1.5
Give 1.5 tablets
30 x = 45
x = 1.5
Give 1.5 tablets
125 mg = 5mL : 100 mg = x mL
125 x = 500
x =4
Give 4 mL
125mg 100mg

5mL
xmL
125mg 5mL

100mg xmL
125 x = 500
x =4
Give 4 mL
125 x = 500
x =4
Give 4 mL
80 mg = 2 mL : 50 mg = x mL
80 x = 100
x = 1.25
Give 1.3 mL
80mg 50mg

2mL
xmL
80mg 2mL

50mg xmL
80 x = 100
x = 1.25
Give 1.3 mL
80 x = 100
x = 1.25
Give 1.3 mL
250 mg = 1 cap : 500 mg = x cap
250 x = 500
x =2
Give 2 capsules
250mg 500mg

1cap
xcap
250mg 1cap

500mg xcap
250 x = 500
x =2
Give 2 capsules
250 x = 500
x =2
Give 2 capsules
80mg 240mg

7.5mL
xmL
80mg 7.5mL

240mg
xmL
80 x = 1800
x = 22.5
Give 22.5 mL
80 x = 1800
x = 22.5
Give 22.5 mL
10mg 20mg

15mL xmL
10mg 15mL

20mg xmL
10 x = 300
x = 30
Give 30 mL
10 x = 300
x = 30
Give 30 mL
80 mg = 7.5 mL : 240 mg = x mL
80 x = 1800
x = 22.5
Give 22.5 mL
10 mg = 15 mL : 20 mg = x mL
10 x = 300
x = 30
Give 30 mL
Page 1 of 5
Problem
7.
Order = 35 mg
Available = 40 mg/2.5 mL
Give___________
8.
Order = 200 mg
Available = 0.5 g per mL
Give___________
9.
Order = 0.05 mg
Available = 50 mcg tablets
Give___________
10.
Order = 100 mg
Available = 50 mg capsules
Give___________
11.
Order = 250 mcg
Available = 2.5 mg per 2 mL
Give___________
12.
Order = 120 mg
Available = 0.12g tablets
Give___________
Linear Ratio-Proportion
Cross-Multiplying RatioProportion
Cross-Multiplying
Ratio-Proportion
40 mg = 2.5 mL : 35 mg = x mL
40 x = 87.5
x = 2.18
Give 2.2 mL
40mg 35mg

2.5mL xmL
40mg 2.5mL

35mg
xmL
40 x = 87.5
x = 2.18
Give 2.2 mL
40 x = 87.5
x = 2.18
Give 2.2 mL
500mg 200mg

1mL
xmL
500mg 1mL

200mg xmL
500 x = 200
x = 0.4
Give 0.4 mL
500 x = 200
x = 0.4
Give 0.4 mL
50mcg 50mcg

1tab
xtab
50mcg 1tab

50mcg xtab
50 x = 50
x =1
Give 1 tablet
50 x = 50
x =1
Give 1 tablet
50mg 100mg

1cap
xcap
50mg 1cap

100mg xcap
50 x = 100
x =2
Give 2 capsules
50 x = 100
x =2
Give 2 capsules
2500mcg 250mcg

2mL
xmL
2500mcg 2mL

250mcg xmL
2500 x = 500
x = 0.2
Give 0.2 mL
2500 x = 500
x = 0.2
Give 0.2 mL
120mg 120mg

1tab
xtab
120mg 1tab

120mg xtab
120 x = 120
x =1
Give 1 tablet
120 x = 120
x =1
Give 1 tablet
500 mg = 1 mL : 200 mg = x mL
500 x = 200
x = 0.4
Give 0.4 mL
50 mcg = 1 tab : 50 mcg = x tab
50 x = 50
x =1
Give 1 tablet
50 mg = 1 cap : 100 mg = x cap
50 x = 100
x =2
Give 2 capsules
2500 mcg = 2 mL : 250 mcg = x mL
2500 x = 500
x = 0.2
Give 0.2 mL
120 mg = 1 tab : 120 mg = x tab
120 x = 120
x =1
Give 1 tablet
Page 2 of 5
Problem
13.
Order = 1 g
Available = 1000 mg tablets
Give___________
14.
Order = Lanoxin 0.25 mg
Available =
Lanoxin 0.125 mg/tablet
Linear Ratio-Proportion
Cross-Multiplying RatioProportion
Cross-Multiplying
Ratio-Proportion
1000 mg = 1 tab : 1000 mg = x tab
1000 x = 1000
x =1
Give 1 tablet
1000mg 1000mg

1tab
xtab
1000mg 1tab

1000mg xtab
1000 x = 1000
x =1
Give 1 tablet
1000 x = 1000
x =1
Give 1 tablet
0.125mg 0.25mg

1tab
xtab
0.125mg 1tab

0.25mg xtab
0.125 x = 0.25
x = 2
Give 2 tablets
0.125 x = 0.25
x = 2
Give 2 tablets
2mg 0.3mg

1mL
xmL
2mg 1mL

0.3mg xmL
2 x = 0.3
x = 0.15
Give 0.2 mL
2 x = 0.3
x = 0.15
Give 0.2 mL
0.1mg 0.2mg

1tab
xtab
0.1mg 1tab

0.2mg xtab
0.1 x = 0.2
x =2
Give 2 tablets
0.1 x = 0.2
x =2
Give 2 tablets
8mEq 20mEq

5mL
xmL
8mEq 5mL

20mEq xmL
8 x = 100
x = 12.5
Give 12.5 mL
8 x = 100
x = 12.5
Give 12.5 mL
0.01mg 0.02mg

2mL
xmL
0.01mg 2mL

0.02mg xmL
0.01 x = 0.04
x =4
Give 4 mL
0.01 x = 0.04
x =4
Give 4 mL
0.125 mg = 1 tab : 0.25 mg = x tab
0.125 x = 0.25
x = 2
Give 2 tablets
Give___________
15.
Order = Morphine gr 1/200
Available =
Morphine 2 mg/mL
2 mg = 1 mL : 0.3 mg = x mL
2 x = 0.3
x = 0.15
Give 0.2 mL
Give___________
16.
Order = Digitoxin 0.2 mg
Available =
Digitoxin 0.1 mg tablets
0.1 mg = 1 tab : 0.2 mg = x tab
0.1 x = 0.2
x =2
Give 2 tablets
Give___________
17.
Order = KCL 20 mEq
Available =
KCL 8 mEq per 5 mL
8 mEq = 5 mL : 20 mEq = x mL
8 x = 100
x = 12.5
Give 12.5 mL
Give___________
18.
Order = Synthroid 0.02 mg
Available =
Synthroid 0.01 mg/ 2 mL
Give___________
0.01 mg = 2 mL : 0.02 mg = x mL
0.01 x = 0.04
x =4
Give 4 mL
Page 3 of 5
Problem
19.
Order = Augmentin 250 mg
Available =
Augmentin 500 mg/5 mL
Linear Ratio-Proportion
Cross-Multiplying RatioProportion
Cross-Multiplying
Ratio-Proportion
500 mg = 5 mL : 250 mg = x mL
500 x = 1250
x = 2.5
Give 2.5 mL
500mg 250mg

5mL
xmL
500mg 5mL

250mg xmL
500 x = 1250
x = 2.5
Give 2.5 mL
500 x = 1250
x = 2.5
Give 2.5 mL
30mg 30mg

1tab
xtab
30mg 1tab

30mg xtab
30 x = 30
x =1
Give 1 tablet
30 x = 30
x =1
Give 1 tablet
10mg 5mg

1tab xtab
10mg 1tab

5mg xtab
10 x = 5
x = 0.5
Give 0.5 tablet
10 x = 5
x = 0.5
Give 0.5 tablet
400mg 800mg

1tab
xtab
400mg 1tab

800mg xtab
400 x = 800
x =2
Give 2 tablets
400 x = 800
x =2
Give 2 tablets
150mg 450mg

1tab
xtab
150mg 1tab

450mg xtab
150 x = 450
x =3
Give 3 tablets
150 x = 450
x =3
Give 3 tablets
5mg 7.5mg

1tab
xtab
5mg 1tab

7.5mg xtab
5 x = 7.5
x = 1.5
Give 1.5 tablets
5 x = 7.5
x = 1.5
Give 1.5 tablets
Give___________
20.
Order = Codeine Sulfate gr 1/2
Available = Codeine Sulfate
30 mg tablets
30 mg = 1 tab : 30 mg = x tab
30 x = 30
x =1
Give 1 tablet
Give___________
21.
Order = Diazepam 5 mg
Available =
Diazepam 10 mg tablets
10 mg = 1 tab : 5 mg = x tab
10 x = 5
x = 0.5
Give 0.5 tablet
Give___________
22.
Order = Clinoril 800 mg
Available =
Dlinoril 400 mg tablets
400 mg = 1 tab : 800 mg = x tab
400 x = 800
x =2
Give 2 tablets
Give___________
23.
Order = Voltaren 450 mg
Available =
Voltaren 150 mg tablets
150 mg = 1 tab : 450 mg = x tab
150 x = 450
x =3
Give 3 tablets
Give___________
24.
Order = Coumadin 7.5 mg
Available =
Coumadin 5 mg tablets
Give___________
5 mg = 1 tab : 7.5 mg = x tab
5 x = 7.5
x = 1.5
Give 1.5 tablets
Page 4 of 5
Problem
25.
Order = Phenobarbital 30mg
Available =
Phenobarbital 15 mg/tablet
Linear Ratio-Proportion
Cross-Multiplying RatioProportion
Cross-Multiplying
Ratio-Proportion
15 mg = 1 tab : 30 mg = x tab
15 x = 30
x =2
Give 2 tablets
15mg 30mg

1tab
xtab
15mg 1tab

30mg xtab
15 x = 30
x =2
Give 2 tablets
15 x = 30
x =2
Give 2 tablets
300mg 600mg

1tab
xtab
300mg 1tab

600mg xtab
300 x = 600
x =2
Give 2 tablets
300 x = 600
x =2
Give 2 tablets
10000units 7500units

1mL
xmL
10000units 1mL

7500units xmL
10,000 x = 7500
x = 0.75
Give 0.8 mL
10,000 x = 7500
x = 0.75
Give 0.8 mL
25mg 12.5mg

1tab
xtab
25mg 1tab

12.5mg xtab
25 x = 12.5
x = 0.5
Give 0.5 tablet
25 x = 12.5
x = 0.5
Give 0.5 tablet
30mg 60mg

1tab
xtab
30mg 1tab

60mg xtab
30 x = 60
x =2
Give 2 tablets
30 x = 60
x =2
Give 2 tablets
750mg 375mg

1tab
xtab
750mg 1tab

375mg xtab
750 x = 375
x = 0.5
Give 0.5 tablet
750 x = 375
x = 0.5
Give 0.5 tablet
Give___________
26.
Order = Tylenol gr X
Available =
Tylenol 300 mg tablets
300 mg = 1 tab : 600 mg = x tab
300 x = 600
x =2
Give 2 tablets
Give___________
27.
Order = Heparin 7500 units
Available =
Heparin 10,000 units/mL
10,000 units = 1 mL : 7500 units =
x mL
10,000 x = 7500
x = 0.75
Give 0.8 mL
Give___________
28.
Order = Capoten 12.5 mg
Available =
Capoten 25 mg tablets
25 mg = 1 tab : 12.5 mg = x tab
25 x = 12.5
x = 0.5
Give 0.5 tablet
Give___________
29.
Order = Codeine gr 1
Available =
Codeine 30 mg/tablet
30 mg = 1 tab : 60 mg = x tab
30 x = 60
x =2
Give 2 tablets
Give___________
30.
Order = Ciprofloxacin
hydrochloride 375 mg
Available = Ciprofloxacin
hydrochloride 750 mg tablet
Give___________
750 mg = 1 tab : 375 mg = x tab
750 x = 375
x = 0.5
Give 0.5 tablet
Page 5 of 5