Let x gallons be the amount of pure antifreeze that should be added to the 30% solution to produce a solution that is 65% antifreeze. Then the total amount of antifreeze solution will be x+3 gallons.
There are 30% of pure antifreeze in 3 gallons of solution, then
3 gallons - 100%,
a gallons - 30%,
where a gallons is the amount of pure antifreeze in given solution.
Mathematically,

Now in new solution there will be x+0.9 gallons of pure antefreeze.
x+3 gallons - 100%,
x+0.9 - 65%
or

Answer: he should add 3 gallons of pure antifreeze.
The sale price of the shirt is $24. And you save $6 from discount.
Answer:
y = -3x
Step-by-step explanation:
Substitute the numbers into the point-slope form equation:
y - 0 = -3(x - 0)
y = -3x
Answer:
d = 13.8 feet
Step-by-step explanation:
Because we are talking about cubic feet of water, we need the formula for the VOLUME of a cylinder. That formula is

We will use 3.141592654 for pi; if the tank HALF filled with water is at 20 feet, then the height of the tank is 40 feet, so h = 40; and the volume it can hold in total is 6000 cubic feet. Filling in then gives us:

Simplify on the right to get

Divide both sides by 125.6637061 to get that

Taking the square root of both sides gives you
r = 6.90988299
But the diameter is twice the radius, so multiply that r value by 2 to get that the diameter to the nearest tenth of a foot is 13.8