Hi, i am having an issue how to approach to this situation, the problem states:- An accident victim arrived at a hospital,who will die unless receive one bag of Rh-positive TypeA (A+) blood within the next 20 minutes.

The blood bank in the hospital have a total 40 bags of blood and 2 bags are A+ blood. However, it is known that the blood type information of the blood bank was missing.

So the nurse would need to re-type the bloods. It takes 2 minutes to examine the blood type of a bag of blood and 2 minutes to complete the transfer of blood.

The hospital staff can only examine one bag of blood at a time. If the first bag of blood examined is not A+, the staff will examine the second bag, if not, the staff will examine the third bag.until he/she is running out of time for saving the patient.

so

What is the probability that the accident victim will be saved in this condition

What is the probability that the victim will not be saved given the A+ blood was not found in the first 10 minutes