For this we only need to observe vertical component. Vertical component is 90 meters/s
The gravity is decresing vertical component at rate of 9.80 m/s because gravity acceleration is 9,80 m/s^2

Simply by deviding starting vertical speed and gravitational acceleration we get time required for  projectile to stop gaining altitude.

90/9.8 = 9,18s

Looking at the answers there isn’t 9.18 offered as answer. But it is indeed answer for the question that has been asked. Maybe you thought that 49m/s is vertical speed than the answer would be 49/9.8=5