Answer:
well,they may or they may not. It all depends on the vertical components of the speed with which the projectile is thrown.
Step-by-step explanation:
to derive the time of flight :
Considering the vertical motion (along y axis) , the journey from the ground to highest point
v=u+at ,where v=final velocity , u=initial velocity , acceleration due to gravity i.e g and t is the time taken by the particle to reach the highest point
o=u(sin theta) + (- g)t
t=u(sin theta) - g
Hence total time of flight is twice of that i.e
T=2(vertical components of speed) / g
So, if two projectile have some vertical components of velocity , they will have equal time of flight.