Question

3Your new mobile phone costs £360.

The probability you leave it on the bus is 0.1.
The probability someone will hand it in to lost property and you will recover it
is 0.4.
The cost of insurance to cover the loss of the phone is £30.
Should you pay for this control measure?
List any assumptions that you make

Answer 1

Assuming you have to pay 30 pounds for somebody handing it in to lost property, you'll have a 0.5 probability that you'll have to pay the 30 pounds if you lose the phone.
Also assuming there are no other ways to lose your phone, you have a 0.5 probability (50% chance?) to lose your phone.
Also assuming the "control measure" is the insurance and you won't have to pay a larger amount, you'll probably be better off paying the 30 pounds instead of the larger amount because you have such a high chance of losing your phone.
I apologize if I misunderstood the question.