Help with a math problem

Sorry if this is in the wrong place. Just trying to find an answer somewhere.


I’m having a problem with scaling up ratios, well I think that's the problem. The problem is regarding the dosage of medicine.


The medicine is 1ml = 300mg, I would like to know the formula to work out how much i need to increase or decrease the amount of ml to get a different amount of mg from a dosage. For example if I want 500mg or 200mg what millilitres of the medicine do I need?

Any help will be greatly appreciated.

 

medicine is 1ml = 300mg

proportion

1ml .................300mg
xml..................200mg
1/xml=300/200
1/xml=3/2
3xml=2
xml=2/3 (200mg is (2/3)(300mg))



1ml .................300mg
xml..................500mg
1/xml=300/500
1/xml=3/5
3xml=5
xml=5/3 (500mg is (5/3)(300mg))

 

Thank you very much for replying!

Honestly from your message I didn’t understand it, however I googled proportion and that was the key word I needed.
Now I believe I understand it.

Direct proportion

1ml = 1000 (Cubic Millimeter)

X is 300(mg) - y is 1000 (Cubic Millimeter)

X 500 - y ?

500x1000 = 500,000

500,000 divide by 300 = 1666.66667 back into ml will be 1.666.

500mg - 1.66ml.

I think that's right.

 

yes, (5/3) =1.666666666666667 or 1.67

 

I like the way you reasoned your way to the answer.

 

Cool. I like the way Rozza reasoned his way or her way to the answer. This is what I want to see---more interaction between members.

 

Thank you very much for your help! I greatly appreciated it.