A regression analysis was performed to determine if there is a relationship between hours of TV watched per day (xx) and number of sit ups a person can do (yy). The results of the regression were:

y=ax+b a=-0.826 b=21.059 r²=0.478864 r=-0.692

Use this to predict the number of sit ups a person who watches 12.5 hours of TV can do, and please round your answer to a whole number.