Question

You have volunteered to be tested for psychic powers. There are 8 cards, 2 of which have a square on them, 2 of which have a triangle on them, 2 of which have a circle on them, and 2 of which have a star on them. The tester shuffles the cards, then looks at each card in turn, without letting you see it, and tries to send the picture psychically to you. You guess a picture randomly each time. Let X be the number of times you guess correctly. What is the probability that you will get 3 pictures right?

Answer 1

Answer:

The probability that you will get 3 pictures right is 0,015625

Step-by-step explanation:

To get the probability, equally likely, of guessing the picture we use the following formula

P=# of possibilities that meet the condition / #of equally likely possibilities.

# of possibilities that meet the condition= 2

#of equally likely possibilities= 8

So every time you guees you have 2 possibilities from 8 ,  that give us a probability of 2/8 or 1/4

We suppose once you guess 1 card ,  the tester put back the card with the others.  

Now,  we must guess 3 pictures,  that will be the multiplication of each probability.

P= 1/4 *1/4*1/4

P= 0,015625