Answer:
50% of the given time period. (number of weeks x 0.50)
Step-by-step explanation:
I didn't see the listed time period, so how ever many weeks they wagered, Multiply that by 0.50, since Shari hits the board 50% of the time.
Without a given time period, there is no way for me to choose form the given answers. I need to know the duration of the bet.
If it were 80 weeks, Shari's mom would give her $40 for 40 weeks.
If it were 120 weeks, Shari's mom would give Shari $40 for 60 weeks.
You see the pattern? :)