Question 42. Ms. A selects a number X randomly from the uniform distribution
on [0; 1]. Then Mr. B repeatedly, and independently, draws numbers
Y1; Y2; :::: from the uniform distribution on [0; 1], until he gets a number
larger than X=2, then stops. The expected number of draws that Mr. B
makes equals
(a) 2 ln 2
(b) ln 2
(c) 2=e
(d) 6=e
Given the information, the first (N-1) of Y_1, Y_2, Y_3, ... , Y_N are less than x/2 and the Nth is greater than x/2. Therefore, Given the info, the conditional distribution of all random variables from Y_1 to Y_(N-1) is the same and equal to uniform U(0, x/2) and of Y_N is U(x/2, 1) and the forth line follows from this.
Series 01, Q3 (Fixed point question). In the solution given by Amit Sir, function g(x) has been assumed as f(x)-x. Now later to prove that g(x) has a fixed point, it has been stated that g(a)>=0 and g(b)<=0 (x belongs to [a,b]). How do we come to this conclusion?
Series 01 Q6-10, I have a doubt, maybe a very trivial one which isn't clicking but would like members to help me clear it out. "Agent 1 strictly prefers bundle (a,b) to bundle (c,d) if, either a > c, or a = c and b > d." does this mean it is a case of perfect substitutes? Because while solving demand for 'x' by agent 1 is m1/px while that of 'y' is zero.
it means the person lexographically prefers x to y....
between two bundles he will demand the bundle that has more of x...and if two bundle has same amount of x ...he will prefer the bundle that has more y..
@shar311 : Q3 - g(a) = f(a) - a.
Now it is given that the function's range is also [a,b]. This means that f(a) belongs to [a,b]. Thus it can be either equal to a, or bigger than a (but less than b). Which means f(a) >= a, and hence g(a) <= 0.