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