Each of the numbers 1 through 10 inclusive has been written on a separate piece of paper. The 10 pieces of paper have been placed in a hat. If one piece of paper is selected at random, with replacement, find the probability that the number selected is:
a. greater than 3
c. odd or greater than 3
d. odd or less than 9
Well, first consider that because we are allowed to return the selected pieces of paper in the hat, then for each of these experiments the all possibilities is C(10,1)=10 which will be the denominator of the probability as you will see.
a) Ok, how many numbers are greater than 3 in the numbers from 1 to 10? They are actually all the numbers from 4 to 10. Therefore we have 7 options. C(7,1)=7. Then P=7/10.
b) How many even numbers are there between 1 and 10 (inclusive)? We have (2,4,6,8,10). Therefore there are 5. And we have ...
Probability of a random selection is calculated.