X + y = 20 --> eqn 1
The second equation would be the mass balance shown below:
(x)(0.40) + y(0.70) = 20(0.52) --> eqn 2
Rearranging eqn 1,x = 20 - ySubstitute this to eqn 2:
(20 - y)(0.40) + y(0.70) = 20(0.52)Solve for y,y = 8 grams Finally, solve for x.x = 20 - 8 = 12 grams
Therefore, Serena needs 12 grams of the 40% solution and 8 grams of the 70% solution.
Answer:

Step-by-step explanation:
We have given the equation y = 6 sin (x)
On differentiating both side 
As it passes through the point 
So 
Now the unit vector is parallel to the tangent so m will be 5.196
This passes through the point 
So unit vector will be 

Answer: 416,592
Hope this helps!
Answer:
R = 5t
Step-by-step explanation:
given s is three times t then s = 3t and
R = 3t + 2t = 5t
7+3=4+6 Both numbers equal 10