Question

Milk and cream contain different percents of butterfat. How much 3% milk needs to be mixed with how much 15% cream go give 20 L if 6% cream?

Answer 1

The 3% milk quantity to be mixed is 15 liters and the the 15% cream quantity to be mixed is 5 liters

Explanation:

The question is

Milk and cream contain different percents of butterfat. How much 3% milk needs to be mixed with how much 15% cream go give 20 L of 6% cream?

Let

x -----> the 3% milk quantity to be mixed

y -----> the 15% cream quantity to be mixed

we know that

`3\%=3/100=0.03`

`15\%=15/100=0.15`

`6\%=6/100=0.06`

`x+y=20`

`x=20-y` -----> equation A

`0.03x+0.15y=0.06(20)`

Multiply by 100 both sides

`3x+15y=120` -----> equation B

substitute equation A in equation B and solve for y

`3(20-y)+15y=120`

`60-3y+15y=120`

`12y=120-60`

`y=60/12`

`y=5\ l`

Find the value of x (equation A)

`x=20-5=15\ l`

therefore

The 3% milk quantity to be mixed is 15 liters and the the 15% cream quantity to be mixed is 5 liters