Question

3. READING In the seventh grade, Rachel

Answer 1

The percent of increase is 20%. 
In order to solve this problem you have to solve this equation:
18-15/15 
3/15
0.2 = 20%

Answer 2

You have to subtract the greater value by the lesser value which is 18-15. Then whatever you got in that problem is the amount of change. Then you do the amount of change divided by the original amount (starting). Whatever you get is the percent increase. Round if needed.
BTW- here's the answer 18-15=3
3/15=0.2   
0.2 is to 2%
2% = percent increase