+0  
 
0
91
1
avatar

In a different plan for area​ codes, the first digit could be any number from 2 through 8​, the second digit was either 4 ,5 , 6 7​, and the third digit could be any number except 5 With this​ plan, how many different area codes are​ possible?

 Apr 3, 2020
 #1
avatar+21013 
0

There are 7 choices for the first digit (2, 3, 4, 5, 6, 7, 8).

There are 4 choices for the second digit (4, 5, 6, 7)

There are 9 choices for the third digit (0, 1, 2, 3, 4, 6, 7, 8, 9).

 

Since these choices are independent, we need to multiply the three numbers:  7 x 4 x 9  to get the correct answer.

 Apr 3, 2020

28 Online Users

avatar
avatar
avatar