Question

A true-false test has 5 questions. What is the probability of guessing the correct answers to all the questions?

A. 1/25
B. 1/10
C. 1/32
D. 1/7

Answer 1

@YanaSidlinskiy

Answer 2

Disclaimer, i could be wrong.


First off, we can easily conclude that its not B or D,

so from my memory(i havent done this in forever) its either 5! or 5^2

5! is 180, so thats not it, and so i would choose A can 5^2 is 25

Answer 3

Thanks

Answer 4

please give me a medal if it is correct.

Answer 5

\[\left(\frac{1}{2}\right)^5\]

Answer 6

\[=\frac{1}{32}\]

Answer 7

Is it A or C?

Answer 8

each question has a 1 in 2 chance of being correct...so a prob of 1/2 (for each t/f question)

if the questions are independent then you multiply the probabilities together...

that is \((1/2)(1/2)(1/2)(1/2)(1/2)=(1/2)^5=1/32\)

Answer 9

Ok thanks @Zarkon

Answer 10

This follows a binomial distribution. X being binomial with p=1/2 and n=5


\[P(X=x)={n\choose x}\left(p\right)^{x}\left(1-p\right)^{n-x}\]

then \[P(X=5)={5\choose 5}\left(\frac{1}{2}\right)^{5}\left(1-\frac{1}{2}\right)^{5-5}=\frac{1}{32}\]

Answer 11

thanks for everything :)