She did 12 questions, and needs to do 36.
36 / 12 = 3, so it will take 3 times as long.
1 hour 20 minutes times 3 = 4 hours.
It will take her 4 hours.
3y + 9x = 12
3y = -9x + 12
y = -3x + 4
If you want function notation you can replace y with f(x)
f(x) = -3x + 4
4 games $80
10 games $200
12 games $240
15 games $300
21 games $420
Hope this helps
