A particle is projected from the ground with some initial velocity making an angle of 45° with the horizontal. If it reaches a height of 7.5 m above the ground while it travels a horizontal distance of 10 m from the point of projection, then the initial speed of particle is
(Assume g =10 m/s2)
1
10 m/s
2
20 m/s
3
15 m/s
4
25 m/s