Answer:
a) 7 weeks b) George's
Step-by-step explanation:
Sally's score can be modeled by 10x+850.
George's score can be modeled by 50x+570.
We can set them equal to each other to see when they intersect.
10x+850=50x+570
40x=280
x=7
If George overtakes her in the 7th week, of course he'll have the higher score in 12 weeks.