Answer:
Pure water =74.1 mL
Step-by-step explanation:
You need 420 mL of a 70% alcohol solution.
420 mL of solution and 70% of it should be alcohol.
So,
420 * 70/100 mL
= 420 * 0.7
= 294 mL of alcohol and the rest should be water.
On hand, you have a 85% alcohol mixture.
The alcohol can only come from the 85% mixture. So, how much of 85% alcohol do we need to get 294 mL of alcohol:
Let
y = alcohol solution needed
85% of y = 294
85/100 * y = 294
y = 294 ÷ 85/100
y = 294 × 100/85
y = 29,400/85
y = 345.88235294117
Approximately, 345.9mL
The rest of 420 mL solution has to be pure water
Pure water = 420 mL - 345.9mL
= 74.1 mL
Pure water =74.1 mL
To calculate a circle's diameter from its circumference, you divide the circumference by the constant pi. So 56 divided by 3.14, which equals 17.83439490445859872611464968152866242. Round that to the nearest whole meter, you get 18 meters. Therefore, the diameter of the barn is 18 meters.
Answer:
65.94 ft.
Step-by-step explanation:
pi*d=C
pi*21=65.94
Given the following question:
First expression:

Second expression:
Answer:
b. y = -9
Step-by-step explanation:
A line with zero slope has no dependence on x. It is simply ...
... y = constant
The constant must be the same as the y-value of the point you want the line to go through. Since the point is (12, -9), the constant is -9 and the equation is ...
... y = -9