X= # gallons of pure water that should be evaporated
The total amount of salt must be equal before and after evaporation.
STEP 1
BEFORE EVAPORATION: multiply the percent of salt in the solution before evaporation by the total gallons of solution
= 12% * 160 gallonsconvert 12% to decimal form (12% ÷ 100)
= 0.12 * 60
STEP 2
AFTER EVAPORATION: subtract the number of gallons of pure water that should be evaporated from the total number of gallons of the solution and multiply by the percent of salt in the solution after evaporation
= 20% * (160 - x)convert 20% to decimal form (20% ÷ 100)
= 0.20(160 - x)
STEP 3
Set the before & after evaporation equations equal to one another to solve for x.
0.12 * 160= 0.20(160 - x)multiply 0.20 by each term in parentheses
19.2= (0.20 * 160) + (0.20 * -x)multiply in parentheses
19.2 = 32 - 0.20xsubtract 32 from both sides
-12.8= -0.20xdivide both sides by -0.20
64 gallons= x
CHECK:substitute x= 64 into the step 3 equation
0.12 * 160= 0.20(160 - x)19.2= 0.20(160 - 64)subtract in parentheses19.2= 0.20(96)19.2= 19.2
ANSWER: 64 gallons of pure water should be evaporated.
Hope this helps! :)
Answer:
Positively skewed
Step-by-step explanation:
This box and whiskers plot represents the data which is right/positive skewed
Answer:
Step-by-step explanation:
Recall the following Pythagorean Identity:
Let's solve the x equation for cos(t) and the y equation for sin(t).
After the solve we will plug into our above identity.
x=5cos(t)
Divide both sides by 5:
(x/5)=cos(t)
y=5sin(t)
Divide both sides by 5:
(y/5)=sin(t)
Now we are ready to plug into the identity:
Multiply both sides by 5^2:
This is a circle with center (0,0) and radius 5.
All I did to get that was compare our rectangular equation we found to
where (h,k) is the center and r is the radius of a circle.
Answer: C
Step-by-step explanation:
Use Desmos | Graphing Calculator <33 This app/website works wonders fro math