Answer:
umm can you tell me which video
Use a fixed mortgage calculator on calculator soup!!!
We need to define the variables,
So,

Therefore, the probability that the repair time is more than 4 horus can be calculate as,

The probability that the repair time is more than 4 hours is 0.136
b) The probability that repair time is at least 12 hours given that the repair time is more than 7 hoirs is calculated as,


The probability that repair time is at least 12 hours given that the repair time is more than 7 hours is 0.63
Answer:
k = 1.91 × 10^-5 N m rad^-1
Workings and Solution to this question can be viewed in the screenshot below: