1. ## Mixture/Solution Problem 2

Hi All,
One term I'm not getting in the below..

Q: 5 litres of water is added to a certain quantity of pure milk costing \$3 per litre. If, by selling the mixture at the same price as before a profit of 20% is made, what is the amount of pure milk in the mixture?

A: Ok so we have 3x as our cost which should be equal to 1.2(3x) (or 120% of 3x given profit). I would imagine the expression therefore to be 3x + 5 = 1.2(3x). However the solution is 3x + 15 = 1.2(3x). Why 15? (I realize this is 3*5 litres of water but not sure why!).

2. Hello, dumluck!

Q: 5 litres of water is added to a certain quantity of pure milk costing \$3 per litre.
If, by selling the mixture at the same price as before, a profit of 20% is made,
what is the amount of pure milk in the mixture?

A: Ok so we have 3x as our cost which should be equal to 1.2(3x)
. . (or 120% of 3x given profit).

I would imagine the expression therefore to be 3x + 5 = 1.2(3x). . No

We have $\,x$ litres of milk.
We add $5$ litres of water.

We have: $x + 5$ liters of mixture, which will sold at \$3 per litre.

Its value is: . $3(x+5)$ dollars.

3. Originally Posted by Soroban
Hello, dumluck!

We have $\,x$ litres of milk.
We add $5$ litres of water.

We have: $x + 5$ liters of mixture, which will sold at \$3 per litre.

Its value is: . $3(x+5)$ dollars.

That makes a lot more sense, thanks for that.

Paul