A body is thrown vertically upwards with velocity u. The distance travelled by it in the fifth and the sixth seconds are equal. The velocity u is given by (g=9.8 m/s2)
The given conditions is possible only when body is at its highest position after 5 seconds
It means time of ascent =5 sec
and time of flight T=2ug=10 ⇒ u=49 m/s