Answer:
2
Step-by-step explanation:
8+6+4+2+1 =21
Total 21 dots/observations
Centre at 11th dot which corresponds to 2
Probability that you will get exactly 4 tails, if you flip a fair coin 7 times is: ![\frac{35}{128}](https://tex.z-dn.net/?f=%5Cfrac%7B35%7D%7B128%7D)
Step-by-step explanation:
We need to find the probability that you will get exactly 4 tails, if you flip a fair coin 7 times.
This is the combination question.
The total combinations will be: 2^7=128
Now, finding number of ways we can get exactly 4 tiles:
We will use the formula:
![^nC_k=\frac{n!}{k!(n-k)!}](https://tex.z-dn.net/?f=%5EnC_k%3D%5Cfrac%7Bn%21%7D%7Bk%21%28n-k%29%21%7D)
in our given question, n= 7, k= 4
Putting values:
![^nC_k=\frac{n!}{k!(n-k)!}\\^7C_4=\frac{7!}{4!*3!}\\ ^7C_4=\frac{7*6*5*4!}{4!*3!}\\ ^7C_4=\frac{7*6*5}{6}\\ ^7C_4=35](https://tex.z-dn.net/?f=%5EnC_k%3D%5Cfrac%7Bn%21%7D%7Bk%21%28n-k%29%21%7D%5C%5C%5E7C_4%3D%5Cfrac%7B7%21%7D%7B4%21%2A3%21%7D%5C%5C%20%5E7C_4%3D%5Cfrac%7B7%2A6%2A5%2A4%21%7D%7B4%21%2A3%21%7D%5C%5C%20%5E7C_4%3D%5Cfrac%7B7%2A6%2A5%7D%7B6%7D%5C%5C%20%5E7C_4%3D35)
So, Probability that you will get exactly 4 tails, if you flip a fair coin 7 times is: ![\frac{35}{128}](https://tex.z-dn.net/?f=%5Cfrac%7B35%7D%7B128%7D)
Keywords: Probability
Learn more about Probability at:
#learnwithBrainly
1. 1/9 since you take all the "a"s in the words which is 2/18
2.2/9 same thing as above
3.18/18 since there is no "O" it's a trick question
4.3/9
5.5/6 since you don't count 6
6.1/2 and 1/2 coins are always 1/2 unless you flip twice
7.5/13
8.1/2 because 1,3,5 odd 2,4,6 even
Hope that helps