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
six
Step-by-step explanation:
the reason is this: let steak be (s), pork be (p), grilled chicken be (gc), tea be (t), and coffee be (c)
now, we want to find the total number of outcomes, and this cannot be determined by a simple roll of the dice. you have to count the sample space required for EVERY outcome, and it has to lie within the conditions. so, assuming David only takes 1 main course and 1 drink, he would be down to six option, which are :
1. s & t
2. s & c
3. p & t
4. p & c
5. gc & t
6. gc & c
F(x)=x^2 +8x
f(d-3) basically what we get from this is that the x value is d-3
to find f(d-3) simply plug in d-3 for every x
f(d-3)=(d-3)^2 + 8(d-3)
that would be one form of the answer, but we can also continue multiplying it out
f(d-3)= d^2-6d+9+8d-24
add like terms
f(d-3)=d^2+2d-15
have a nice day and i hope this helps :)
Correct answers
1). first option
4) last option
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