You can find a common demominator and then change 8 1/4 into a mixed number and just subtract
well, in short, the students and chaperones are at a 2 : 9 ratio, and we know there are 171 students, how many chaperones then, so long they maintain a 2:9 ratio?

Answer:
170
Step-by-step explanation:
Equations derived from given info.
Use some substitution now.
- P=2(E+40)
- J=E+40
- P+J+E=300
Substitute first and second equation into third.
- 2(E+40)+E+40+E=300
- 2E+80+E+40+E=300
- 4E+120=300
- 4E=180
- E=45
Emily has 45 stickers. But we want to know what Peter has.
Use P=2(E+40)
Peter has 170 stickers.
Answer: Sara multiplied by 3 when she should have multiplied by 8.
Step-by-step explanation:
21 : 7*8
7*8 = 56
21 : 56
The simplest form of this ratio is 3 : 8