Question 260698
We have two points
(30,620)
(70,788)
y-y/x-x=m
788-620/70-30=m
168/40=84/20=42/10=4.2=m
y=4.2x+b
620=4.2*30+b

b=494
y=4.2x+494 equation
y=4.2*55+494=725 predicted score for 55 hours
No need to round.