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
It would shift up, that is the anwser
Ok so
t=number of text messsages
p=number of picture messages
total number is 33
t+p=33
if text is 0.18 per pic and picture is 0.45 per text
total cost is 8.3
0.18t+0.45p=8.3
times 100 both sides for ease
18t+45p=830
we now have 2 equations
t+p=33
18t+45p=830
multiply first equation by -18 and add to second equation
18t+45p=830
<span>-18t-18p=-594 +</span>
0t+27p=236
27p=236
divide both sides by 27
p=8.740740740740744
this is impossible becasue you can't send 0.740740740740744 of a message so you did a mistype somewhere
Answer:
The volume ratio is also 5 : 7
Step-by-step explanation:
The volume of a cylinder is given by the following formula:
volume = pi*r²*h
Since we have two cylinders and their height varies at a ratio of 5:7 we can say that the smaller one has a height of "h" while the bigger has height of "(7/5)*h". Thefore their volume is:
volume smaller = pi*r²*h
volume bigger = pi*r²*(7/5)*h
volume bigger = (7/5)*pi*r²*h
The ratio of their volume is given by the division of the smaller volume by the bigger one:
volume ratio = volume smaller / volume bigger
volume ratio = (pi*r²*h) / [(7/5)*pi*r²*h] = 1/(7/5)
volume ratio = 5/7
The volume ratio is also 5 : 7.
You don't need to understand the construction or why it works. You only need to accept the fact that it does. You can figure out the answers to this question by looking at the picture.
RT is tangent to circle Q -- TRUE. That is the point of the construction.
QT is a radius of circle Q -- TRUE. Q is the center and T is on the circle. A line segment from the center to a point on the circle is a radius.
m∠QSR = 90° -- FALSE. Those points lie on the same line. The measure of the angle is 180°.
QS = QT -- FALSE. S lies inside circle Q, so is closer to the center than T, which lies on the circle. (For some choice of point R, S might lie on the circle, but because this statement is not always true, it must be considered false.)
ΔRTQ is a right triangle -- TRUE. A tangent line is always perpendicular to the radius to the point of tangency. The construction succeeds because RTQ is inscribed in semicircle RTQ (centered at S). Such a triangle is always a right triangle.
