Answer:

Step-by-step explanation:
We start off with 3.2n + 13.3 = 26.1.
We need to get n by itself.
Subtract 13.3 from both sides.


We end up with: 
Divide 3.2 on both sides to get n by itself.

Answer: a. 10%
Step-by-step explanation:
Girls in the class = 40%
Girls play tennis = 25%
Percentage of class play tennis = 40%*25% = 0.4*0.25 = 0.1
Percentage of class play tennis = 10%
300. if you sold a third. then 2/3 would be left. you can then infer each is 300