Robert claims that his dog can do single-digit multiplication. he shows the dog 8 cards with simple multiplication problems that are either correct or incorrect. the dog correctly identifies the correctness of the card 5 times out of 8. if the dog were simply guessing, how many would the dog be expected to get correct?
5
8
13
4

Fourth option is correct.

Step-by-step explanation:

Since we have given that

Number of cards = 8

Probability of the correctness of the car =

Since there are two possibilities of the card i.e. correct and incorrect.

Let the number of correct answer that his dog chooses be 'x'.

Since we will apply Binomial theorem:

n = 8

p =

So, Mean would be

Hence, Fourth option is correct.

they charge the same amount at 20 minutes.

step-by-step explanation:

60: 45 =12: 9 =4: 3 so the answer is 4: 3