Answer:
 12s
Step-by-step explanation:
Given parameters: 
Velocity = 7.5m/s 
Distance = 90m 
Unknown: 
Time taken = ? 
Solution: 
Speed is the rate of distance traveled with time. It is mathematically expressed as; 
 Speed = 
 
 
 Since the unknown is time; 
 Time = 
 
 
 Insert the parameters and solve; 
 Time = 
 = 12s
 = 12s