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.
440 degrees in 32 seconds
8X4=32
110X4=440
.27 repeating is 3/11
The standard notation for a repeating decimal is to put a bar over the repeating digits, that is, <span>0.27272727...=0.27 repeating
</span>
The answer is c hope this helps :)
