What is the least common denominator of 5/12 and 4/9

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?

This is about circle theorems. someone asap : (

Jordan got 27 out of 90 correct on his test . what fraction of the marks did her get correct