Given s=16t^2 where s=distance in feet travelled (downwards) since airborne with zero vertical velocity and zero air-resistance t=time in seconds after release
Here we're given s=144 feet => s=144=16t^2 => t^2=144/16=9 so t=3 Ans. after 3 seconds, the object hits the ground 144 ft. below.
Your graph is correct. You start with point (0, 40). On day 0, you have 40 T-shirts. Each day that passes, you have 5 shirts fewer. (1, 35) means on day 1, you have 35 shirts left. Each day that passes, there are 5 fewer shirts. On the 8th day, there are no shirts left. That is point (8, 0).
