Probability question.

[collegekid]

The local pet store held a contest in which they drew ten children’s names as semifinalists. They then held another drawing from among those ten to determine who would win the top two prizes: a pair of homing pigeons or a cockatiel. The ages of the semifinalists were 4, 5, 6, 7, 9, 10, 11, 13, 15, and 16. When the two winners’ names were drawn, the older winner was a teenager. What is the probability that the younger winner’s age was prime?

 

[Deleted member 4993]

The local pet store held a contest in which they drew ten children’s names as semifinalists. They then held another drawing from among those ten to determine who would win the top two prizes: a pair of homing pigeons or a cockatiel. The ages of the semifinalists were 4, 5, 6, 7, 9, 10, 11, 13, 15, and 16. When the two winners’ names were drawn, the older winner was a teenager. What is the probability that the younger winner’s age was prime?

How many prime numbers are there - and smaller than a teen?

Please share your work with us, indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[collegekid]

Prime 5,7,9,11,13
younger than a teen 7 people.

my initial answer to this was three out of 7, three prime numbers out of 7 people younger than a teen but my professor said this is not correct. i was thinking the amount of prime numbers over the amount of remianing people. any different suggestions.

 

[Denis]

The ages of the semifinalists were 4, 5, 6, 7, 9, 10, 11, 13, 15, and 16. When the two winners’ names were drawn, the older winner was a teenager. What is the probability that the younger winner’s age was prime?

if older = 15 or 16 : 5,7,11,13
if older = 13 : 5,7,11
Play with that!

 

[collegekid]

would the correct answer be 4/10?

there are 4 prime numbers out 10 total that are younger than a teen?