Answer:
The chemist needs to add 400mL of 40% solution.
Step-by-step explanation:
The equation
gives the percent concentration of the final mixture, when
mL of the 40% solution are added.
Now we are asked, how many milliliters of the 40% solution should the chemist add to get final percent concentration
; this is just a matter of solving the equation
and we solve it the following way:
Thus, the chemist needs 400mL of 40% solution to get 30% concentration of the final mixture.
The steps in the patterns A and B form a sequence
The attached diagram represents dots in patterns A and B
<h3>How to draw the diagrams</h3>For pattern A, we have:
Step 2 = 10 dots
Increment of 3 dots in each step
This means that:
Step 0 = 4 dots
Step 1 = 7 dots
Step 2 = 10 dots
Step 3 = 13 dots
For pattern A, we have the following rule
When n = 0 to 3, we have:
Step 0 = 1 dot
Step 1 = 3 dots
Step 2 = 9 dots
Step 3 = 19 dots
Next, we draw the diagrams of both patterns (see attachment)
Read more about patterns at:
