Answer:
Let's call the first studio, yoga studio A.
Let's call the second studio, yoga studio B.
The equations:
Yoga Studio A: y=10x+55
Yoga Studio B: y=12.5x+25
So, for 12 classes:
Yoga Studio A: y=10(12)+55, y=175
Yoga Studio B: y=12.5(12)+25, y=175
These two numbers are equal, so Griffin is right.
For 10 classes:
Yoga Studio A: y=10(10)+55, y=155
Yoga Studio B: y=12.5(10)+25, y=150.
These two numbers are not equal, so Gigi is wrong.
Let me know if this helps!