Today,during the maths lesson we were doing some researches in the ICT room. I have found very intresting quiz(at least it seems intresing to me). This quiz is simplified famous game "deal or no deal".
There are 3 doors in these game. Behind 2 of them are goats and behind one is a car.Player chooses one door and after that presenter opens one of the unopened doors with the goat. After that he offers player to change a door he has chosen. The question is if it's reasonable to change doors or not.
The answer is that it's better to change the doors.
The solution
let's devide these 3 doors into 2 groups. First group has only one door that is chosen by the player. The other group has 2 unopened doors. The chance that the car is in the first group is 33%(because there is one car and 3 doors) the chance that the car is in the second groups is 66%. Now the presenter opens one door with a goat in the second group. Some people may think that now chances are 50/50 but they are not. Now second group can be opened at one time(because there is only one unopened door left) but the chance that the car is in the second group is 66% and that the car is the first group is only 33%. So it's reasonable to swap the doors.
Current ratio
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The current ratio is a financial ratio that shows the proportion of current
assets to current liabilities. The current ratio is used as an indicator of
a c...
6 years ago
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A draw contains red socks and black socks. When two socks are drawn at random, the probability that both are red is 0.5.
(a) How small can the number of socks in the drawer be?
(b) How small if the number of black socks is even?
You have R red socks and B black socks. the probability that you draw 1 red sock is R/(R+B) the probability that you will take the next one red is (R-1)/(R+B-1). The probabilty that both of these situation succed is
(R*R-R)/(R+B-1)*(R+b)and it equals 1/2.
so
r=(1+2b-squareroot(8*b*b+1)/2
or r=(1+2b+squareroot(8*b*b+1)/2
but we need to lower the number so b=1 so either r=0(that's useless) or r=3. So the number is 4.
b)We need both r and b to be integers. So we substitute b with 2 4 6 and we get that when b=6 then r is 15 so we get that the second is 21.
succeed*
Coupons in cereal boxes are numbered 1 to 5 and a set of one of each is required for a prize. With one coupon per box how many boxes on the average are required to make a complete set?
12)write a blog everyday.
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