h = 125 mExplanation:Hello Friend, LETS say that the stone is in motion for ' t ' seconds.Distance covered by the stone in first 4 seconds:u = 0 , t =4 , a = 10s = 1/2 x 10 x 16 = 80 mIn last two seconds:The stone would already have some velocity DUE to it's drop from intitial position. Let us find this velocity:t = t -2 (since only two seconds are left in motion) , u = 0 , a =10v = 10(t-2)The stone would have a velocity of 10 (t-2) two seconds before it hits the ground.So,u = 10(t-2) , a = 10 , t =2 (as it is given only two seconds are left in motion) ,         s = 80 (as it is given distance covered in first 4 seconds is equal to this distance)80 = 10(t-2)2 + 5(4) => 80 = 20t - 40 + 20 => t = 5 secondsTherefore the stone is in motion for 5 seconds.IN the questions, they demand us to find h.h = 1/2 x 10 x (25)Therefore h = 125 m Dear friends, I have directly applied equations of motions here. Please understand it, I used only s = ut + 1/2 at^2 and v = u + at , nothing else.If you LIKE the answer please mark me as brainliest and also give me thanks.