Answer:
8.46 gallons needed to be replaced
Step-by-step explanation:
Let x be the alcohol amount that replaced
-Original has concentration of 15% multiply by the amount of 10 ,which is equal to (0.15×10).
-Removed has concentration of 15% multiply by the amount of x ,which is equal to (0.15 × X).
-Added has concentration of 80% multiply by the amount of X ,which is equal to (0.8× X).
-Solution has concentration of 70% multiply by the amount of 10 ,which is equal to (0.70×10).
So that, the equation will be:
Solution=Original + added - removed
7=1.5+0.8x-0.15x
7-1.5=0.65x
0.65x=55
x=55/0.65
x=8.46
8.46 gallons needed to be replaced.
The graph of the function f(x)=3(2)^x -4 passes through the points (0,-1), (1,2), (2,8) and (3,20)
<h3>What are exponential functions?</h3>
When the expression of function is such that it involves the input to be present as exponent (power) of some constant, then such function is called exponential function.
here usual form is specified below. They are written in several such equivalent forms.
The equation of the function is given as:

Set x = 0, 1, 2 and 3

This means that the graph of the function f(x) = 3(2)^x -4 passes through the points (0,-1), (1,2), (2,8) and (3,20).
Read more about exponential graphs at:
brainly.com/question/11832081
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Answer:
20 people
Step-by-step explanation:
In this problem, you are solving for 5% of 400. All percentages are out of 100, meaning 5% equals 0.05 because 5 ÷ 100 = 0.05
1. Multiply 400 by 5% (0.05)
400 · 0.05 = 20 people
Answer:
4,2,1
Step-by-step explanation: