A ball is thrown vertically upward from the top of a building 1600 feet tall with an initial velocity of 80 ft per second. The distance d(t), in feet, of the ball from the ground after t seconds is d(t)=1600+80t-16t^2 . After how many seconds is the ball at its maximum height? Find the maximum height of the ball. How long will it take the ball to hit the ground?

Step-by-step explanation:

Function given

Maximum height is the vertex of the parabola, which is achieved at:

Substituting values of a and b

Value of d(2.5):

Time to hit the ground:

Solving we get positive root:

step-by-step explanation:

why? because i noticed a pattern. 60 120. those numbers without the zero, make the 6 times tables leaving your answer to be b since 6 times 4 is 24 and adding a zero making it 240.