Let the first body is thrown with the velocity u from the ground.

at maximum height, v = 0

using formula, v² = u² + 2as

or, 0 = u² + 2(-g) × 50

or, u² = 100g

or, u = √(100g) m/s

the 2nd body is thrown with velocity , v = 2u = 2√(100g) m/s

we have to find height reached by second body.

i.e., s = v²/2g = {2√(100g)}²/2g

= 4 × 100g/2g

= 200 m [Ans]