Please help!

[monabhola]

1. Solve the formula V1 = P2 for V1
V2 = P1

2. How many litres of a 25% alcholol solution must be added to 4.2 L of 45% alcohol solution to make a 30% solution?

3. The difference of 3 times a number and 15 is -6. Find the number

 

[Deleted member 4993]

1. Solve the formula V1 = P2 for V1
V2 = P1

2. How many litres of a 25% alcholol solution must be added to 4.2 L of 45% alcohol solution to make a 30% solution?

3. The difference of 3 times a number and 15 is -6. Find the number

Your expression is: \(\displaystyle \dfrac{V_1}{V_2} \ = \ \dfrac{P_2}{P_1}\)

What do you get if multiply both sides by V₂?

Please share your work with us, indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[monabhola]

V1=P2 for V1
V2=P1
V1xP1=V2XP2 V1=(V2XP2)/P1 ????????? Not sure

The difference of 3 times a number and 15 is -6. Find the number
X=a number
15-3x=-6
-3x=-6-15
-3x=-21
x=7 (however this answer is incorrect)

How many litres of a 25% alcohol solution must be added to 4.2 L of a 45% alcohol solution to make a 30% solution?
I do not know