A stone thrown vertically upward twice was at the same height 0.8 and 1.5 s after the start of the movement.

A stone thrown vertically upward twice was at the same height 0.8 and 1.5 s after the start of the movement. what is this height equal to?

Movement up and down can be considered uniformly accelerated.
The time is the same for ascent and descent.
Those. the body fell from the highest point to this height (1.5-0.8) /2=0.35c.
The body was at the point twice, during the rise and fall.
It rose 0.8 s, therefore, the height
h = g * 0.8 ^ 2/2 = 3.2m.