Physic~ about gravity

Use equation of motion: s = vt - (1/2)gt^2 for the upward journey
with s = 37.5 ft., v = 0 m/s, t = 5/2 s = 2.5 s, a = -g (the acceleration due to
gravity)
Hence, 37.5 = -(1/2)(-g).(2.5^2)
g = 2 x 37.5/2.5^2 ft/s^2 = 12 ft/s^2

p.s. The correct value of g on earth should be 32 ft/s^2. Please check if the given data are correct.