Answer :
Answer: time is 67,5 s
Explanation: 21/4 seconds is 2.25 second and marble rolls 1/30 part of the path.
The marble needs whole path 30·2.25 seconds, also 67.5 s
Answer: time is 67,5 s
Explanation: 21/4 seconds is 2.25 second and marble rolls 1/30 part of the path.
The marble needs whole path 30·2.25 seconds, also 67.5 s