Answer:
maximum height reached = 35 feet
and

Explanation:
writing linear motion equations

where s is the total displacement, u the initial velocity, t the time travelled, and a is the acceleration.
given u = 48 ft/s, and a = acceleration due to gravity g = -9.8

1 m = 3.28 feet therefore g becomes -9.8×3.28

here negative sigh comes as acceleration due to gravity is in opposite direction of initial velocity.
therefore f(t) becomes

to find max height we should find differentiation of f(t) and equate it to 0
therefore we get 48 = 32.144t
t = 1.49 s
therefore max height f(1.49) = 71.67-36.67 = 35 feet