A percent is a number out of 100, so you'd want to multiply the denominator to get 100. In this case, 25 would have to be multiplied by 4 to get 100. To keep the fractions equal to each other, you have to multiply the numerator by the same thing. 2*4=8. Therefore, your fraction would be 8/100 or 8%
Answer:
Expected time is 15 hours for him to get to safety.
Step-by-step explanation:
We define X as the time that this miner would get to safety.
We define Y as the door he chooses initially.
P(Y= 1) = P(Y=2)=P(Y=3) = 1/3
We have E[X|Y=1] = 3
E[X|Y] = 5 hours + E[X}
E[X|Y] = 7 hours + E[X]
Then we have
E[X] = 1/3(3 + 5 + E[X] + 7 + E[X])
We cross multiply
3*E[X] = (15 + 2E[x])
3E[X] - 2E[X] = 15
E[X] = 15
So the time it would take to get him to safety is 15 hours
The first on is this answer here
