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
Let's separate this shape into three parts. A smaller rectangle at the top, and one at the bottom, and a bigger rectangle in the middle.
The smaller rectangle at the top:
The equation to find the area of a rectangle is
(a = area, l = lenght, w = width)
a = l · w
Put in the values
a = 18 · 3
a = 54
Since the smaller rectangle at the bottom has the same length and width, it has the same area.
The bigger rectangle in the middle:
a = l · w
Put in the values
a = 8 · 9
a = 72
Now add all of the areas together to get the answer!
72 + 54 + 54 = 180
The answer is 180 :)
Hopefully this helps! If you have any more questions or don't understand, feel free to DM me, and I'll get back to you ASAP! :)
Answer: ar·ith·met·ic pro·gres·sion
/ˌeriTHˌmedik prəˈɡreSH(ə)n/
noun
a sequence of numbers in which each differs from the preceding by a constant quantity (e.g., 3, 6, 9, 12, etc.; 9, 7, 5, 3, etc.).
the relationship between numbers in an arithmetic progression.
"the numbers are in arithmetic progression"
Step-by-step explanation:
