johnathan needs 70 liters of a 50% alcohol solution. he has a 30% solution and an 80% solution available. How many liters of the 30% solution and hjow many liter of the 80% solution should he mix to make the 50% solution?

28 l of 80%

42 l of 30%

Step-by-step explanation:

Target is 70 l of 50% solution

It will contain 70*0.5= 35 l of alcohol

x l of 80% solution and y l of 30% solution mixed to get the target solution

x+y=70 is the equation for total volume, and

0.8x+0.3y= 35 is the equation for the alcohol content. Solving this:

then

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

could you reply to this with the question so i can ?