MWizard2k04

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UsernameMWizard2k04
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 #1
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A randomiser of n bits (base 2 unsigned)

n = 1 2 3 4 5 6 7 8 9 10
Number of possible ways 2 2 4 8 16 32 64 128 256 512
Number range

0

1

10

11

100

101

110

111

1000

1001

1010

1011

1100

1101

1110

1111

10000

10001

10010

10011

10100

...

11100

11101

11110

11111

100000

100001

100010

100011

100100

...

111100

111101

111110

111111

... ... ... ...

 

When n ≥ 2, we have 2n possible ways to store numbers.

 

Number of consecutive Heads:

 

10 heads + 90 random (1st ~ 10th try, 2nd ~ 11th try ... 91st ~ 100th try)

91 tries × 290 = 112 652 543 574 969 605 015 820 304 384

11 heads + 89 random (1st ~ 11th, 2nd ~ 12th ... 90th ~ 100th try)

90 tries × 289 = 55 707 301 767 842 112 370 460 590 080

12 heads + 88 random

89 tries × 288 = 27 544 165 874 099 711 116 505 513 984

...

The information above is an assumption; we do it by working backwards and finding a pattern.

97 heads + 3 random (97H, T, T, T; 97H, T, T, H; 97H, T, H, T; 97H, T, H, H  )

4 tries

98 heads + 2 random (98 heads, 1 tail, 1 head or 98 heads, 2 tails)

2 tries

99 heads + 1 tails

1 try

100 heads

1 try

 

 

                       100H   99H         98H            97H        96H            95H                  11H                  10H

Thus, we have 1 + (21 - 20) + (22 - 21) + (23 - 22) + (24 - 23) + (25 - 24) + ... + (289 - 288) + (290 - 289) = 290 = 

                        ||

                        20

1 237 940 039 285 380 274 899 124 224 ways.

 

Do some cancellation. Remove the brackets as there is only + outside of brackets, and a + (b - c) = a + b - c.

 

Thus, the probability of getting at least 10 consecutive heads is:

 

Percentage : \(8.0779356694631608 \times 10^{-28} %\)

Fraction : \(1 \over 1 237 940 039 285 380 274 899 124 224\)         

My Calculator

Brand: Casio

Model: fx-96SG PLUS

Type: Natural-V.P.A.M.

Digit Display: 10 digits

Calculation Input: 15 digits

Calculation Range: \(1 \times {10}^{-99} ≤ |x| < 1 \times {10}^{100} \, or \, 0\)

.
Apr 21, 2016