Answer:
355 milliliter.
Step-by-step explanation:
Given:
A certain drug is made from only two ingredients: compound A and compound B.
There are 5 milliliters of compound A used for every 4 milliliters of compound B.
If a chemist wants to make 639 milliliters of the drug, how many milliliters of compound A are needed ?
Solution:
<u>As 5 milliliters of compound A is used for every 4 milliliters of compound B.</u>
Ratio of compound A and compound B = 5 : 4
Let ratio be
Quantity of compound A in milliliter =
Quantity of compound B in milliliter =
Now, we have to make 639 milliliters of the drug,
<u>Quantity of compound A + Quantity of compound B = 639 milliliters</u>
Dividing both sides by 9
Quantity of compound A in milliliter = =
Therefore, 355 milliliter of compound A are needed to make 639 milliliters of the drug.