+0  
 
+1
240
2
avatar+394 

Chris wants to put six plants in a row on his windowsill. He randomly chooses each plant to be an aloe plant, a basil plant, or a violet. What is the probability that either exactly four of the plants are aloe plants or exactly five of the plants are basil plants?

Mr.Owl  Dec 9, 2017
Sort: 

2+0 Answers

 #1
avatar+92448 
+3

Hi Mr Owl,

 

Chris wants to put six plants in a row on his windowsill. He randomly chooses each plant to be an aloe plant, a basil plant, or a violet. What is the probability that either exactly four of the plants are aloe plants or exactly five of the plants are basil plants?

 

The number of ways that the 6 plants can be arrangesd is 3^6 = 729

 

The number of ways that the first 4 plants are aloe vera and the last 2 are not is  1*1*1*1*2*2 = 4

The number of ways that exactly 4 plants are aloe vera is   6C4*4 = 15*4 = 60

 

The number of ways that the first 5 plants are basil   1*1*1*1*1*2 = 2

The number of ways that the first 5 plants are basil    6C5*2 = 6*2=12

 

There are no overlaps with these so

 

The probabity you want is  (60+12) /  729 = 72/729 =   8/81

Melody  Dec 9, 2017
 #2
avatar+394 
+3

Thanks! 8/81 Was the right answer! Thanks a bunch!

Mr.Owl  Dec 10, 2017

17 Online Users

New Privacy Policy (May 2018)
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  Privacy Policy