Calculus: with what initial velocity much an object be thrown upward (from ground level) to reach the top of the washington monument (approximately 550 feet)?

S = Kt - 16t^2 

setting s = 550 
550 = Kt - 16t^2 

this will reach the highest point when v = 0 
t = K/32 
when t = K/32 
550 = K^2/32 - K^2/64 
K^2 = 550*64 
K = 187.62 ft/s