okay, so i've gotten that the intial velocity of the balls is 7.75 m/s and that the time required for a ball to hit the ceiling is 0.775 seconds. the answer sheet tells me this is right. so i thought that, considering the situation, the balls would pass eachother halfway through their trips, at 1.5 m. so i solved the quadratic that gave me how long it would take the second ball to reach 1.5 m and i got 0.175 seconds. this is wrong. how come? if they dont pass each other halfway through their trips then when?

thanks in advance