A rock is thrown vertically up from the ground with a velocity of 24 meters per second, and it reaches a height of 2+24t-4.9tsquare after t secounds.

A. How many seconds after the rock is thrown will it reach its maximum height?

B.What is the maximum height the rock will reach, in meters?

C. How many seconds after the rock is thrown will it hit the ground?

It will reach the max height after 2.45 secs.
You can find the max height by differentiation and setting it to zero. ie. 24 -9.8 t = 0 and solve for t to be 2.45 secs.
Then use 2.45 in the equation to find the max height to be 2 + 24 *2.45 + 4.9 (2.45)(2.45) = 90.21 meters.
It will hit the ground in 2.45 * 2 secs = 4.90 secs