Let's denote the height of the tower as 'h'.
For the first stone that is dropped, we can use the equation of motion to calculate its distance traveled in 1 second:
s₁ = ut + (1/2)at² s₁ = (0 m/s)(1 s) + (1/2)(9.8 m/s²)(1 s)² s₁ = 0 + (1/2)(9.8 m/s²)(1 s²) s₁ = 4.9 m
The distance traveled by the first stone in 1 second is 4.9 meters.
Now, let's consider the second stone that is thrown vertically downwards at a speed of 15 m/s. Since it starts with an initial velocity in the downward direction, we need to take this into account when calculating its distance traveled in 1 second:
s₂ = ut + (1/2)at² s₂ = (15 m/s)(1 s) + (1/2)(9.8 m/s²)(1 s)² s₂ = 15 m + (1/2)(9.8 m/s²)(1 s²) s₂ = 15 m + 4.9 m s₂ = 19.9 m
The distance traveled by the second stone in 1 second is 19.9 meters.
Since both stones meet or reach the ground simultaneously, the total distance traveled by both stones must be equal to the height of the tower:
s₁ + s₂ = h 4.9 m + 19.9 m = h 24.8 m = h
Therefore, the height of the tower is 24.8 meters.