Problem Of The Week 42
Let their be 7 special coins such that they are numbered from 1-7 on one side and blank on the other side. You toss all the 7 and let them fall and make your best guess as to which coin is 1, what is the probability that you are correct?
The best case scenario could be that they all fall in a row from 1to 7
ReplyDeleteProbability
4/32 = 1/8
we dont want the best case
ReplyDeletebest case will be when one turns up
:)
we want the best guess
There are total 8 cases
ReplyDeleteCase 1 : When all the coins fall as blank.
Case 2 : When one coin fall blank and rest 6 as numbered.
Case 3 : When 2 coin fall blank and rest 5 as numbered.
Case 4: When 3 coin fall blank and rest 4 as numbered.
Case 5 : When 4 coin fall blank and rest 3 as numbered.
Case 6: When 5 coin fall blank and rest 2 as numbered.
Case 7: When 6 coin fall blank and rest 1 as numbered.
Case 8: When all coin fall as numbered.
Thus the probability will be 1/2 + 1/2[(1/2)^6+(1/2)^5*1/2*1/2+(1/2)^4*(1/2)^2*(1/3)+(1/2)^3*(1/2)^3*(1/4)+(1/2)^2*(1/2)^4*(1/5)+(1/2)*(1/2)^5*1/6]
rightly done riya !
ReplyDelete