Naplex calculation Math problems

[li10brarian87]

---

Members don't see this ad.

hey guys can anyone help in understanding the naplex sdn math calculation problems.. in the pdf file .. problem no 11.. i understood till most but last part where it 3510 divide by 234.. didint understand that part.. y dont we subtract that .. plus in same problem .. there is lot of changes from grams to milligrams .. how do you know ? for example 1000ml has 234 mg not 234 grams .. how ? how to determine when it will be in milligrams n when in grams...adiitionally in problem no 12 .. alligation is used .. how to realize on the test that its a question of alligation .. Can some1 help me in this ..?

 

[Dred Pirate]

please, for all things holy, type in complete sentences and don't use txt slang

 

[zelman]

hey guys can anyone help in understanding the naplex sdn math calculation problems.. in the pdf file .. problem no 11.. i understood till most but last part where it 3510 divide by 234.. didint understand that part.. y dont we subtract that .. plus in same problem .. there is lot of changes from grams to milligrams .. how do you know ? for example 1000ml has 234 mg not 234 grams .. how ? how to determine when it will be in milligrams n when in grams...

You need to divide 3150mg by 234mg/mL because otherwise the units would make no sense. Always make sure your units work.

Also, percentages w/v are grams per 100mL (I remember by figuring out what's in 100% water). They transformed this into 23.4% = 234mg/mL, but it's the same thing.
234mg/mL = 0.234g/mL = 23.4g/100mL

adiitionally in problem no 12 .. alligation is used .. how to realize on the test that its a question of alligation .. Can some1 help me in this ..?

You can do this any way you want. I'd probably just use algebra:

70g/100mL * x = (10 g / 100 mL) * (1015 + x) mL

(I'm going to take out units now for the sake of laziness)

((70/100)/(10/100)) * x = 1015 + x
7 * x = 1015 + x
6 * x = 1015
x = 1015/6

(and now the units magically reappear...still for laziness)

x ≈ 169.2 mL

 

[li10brarian87]

You need to divide 3150mg by 234mg/mL because otherwise the units would make no sense. Always make sure your units work.

Also, percentages w/v are grams per 100mL (I remember by figuring out what's in 100% water). They transformed this into 23.4% = 234mg/mL, but it's the same thing.
234mg/mL = 0.234g/mL = 23.4g/100mL



You can do this any way you want. I'd probably just use algebra:

70g/100mL * x = (10 g / 100 mL) * (1015 + x) mL

(I'm going to take out units now for the sake of laziness)

((70/100)/(10/100)) * x = 1015 + x
7 * x = 1015 + x
6 * x = 1015
x = 1015/6

(and now the units magically reappear...still for laziness)

x ≈ 169.2 mL

Thankyou so much