A ball is thrown into the air with an upward velocity of 100 ft/s. Its height, h, after t seconds is given by the function h=-16t^2 +64t +960. When did the ball hit the ground? a) 10 seconds

b) 7 seconds

c) 5 seconds

d) 2 seconds

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.