When clark was 7 years old he had 22 rare coins. each year clark added 15 coins to his collection. assuming clark does not sell or lose any coins, how old will clark be when he has 577 coins?
a) 30
b) 31
c) 37
d) 44

Cherie works in retail and her weekly salary includes commission for the amount she sells. the equation s=400+0.15c models the relation between her weekly salary, s, in dollars and the amount of her sales, c, in dollars. interpret the slope of the equation.