+0  
 
0
103
1
avatar

Can anyone give me some guidance here?

 

A special type of door lock has a panel with five buttons labeled with the digits 1 through 5. This lock is opened by a sequence of three actions. Each action consists of either pressing one of the buttons or pressing a pair of them simultaneously. For example, 12-4-3 is a possible sequence. The sequence 12-4-3 is the same as 21-4-3 because the 12 or the 21 simply means to press buttons 1 and 2 simultaneously.
(a) How many different sequences are possible?
(b) How many different sequences are possible if no digit (or pair of digits) is repeated in the sequence?

 Mar 13, 2020
 #1
avatar+286 
+3

a) On each action, there are 15 possible inputs: 5 inputs consisting of a single button, and 10 inputs consisting of two different buttons.

 Mar 13, 2020

4 Online Users

avatar