To log on to a certain computer account, the user must type in a 4-letter password. In such a password, no letter may be repeated, and only the lower case of a letter may be used. How many such 4-letter passwords are possible

 358800

Step-by-step explanation:

To create a four-letter password such that no letter are repeated and only lower cases are used;

For the first letter, we can choose any letter from A to Z = 26

We can choose any letter from A to Z except for the first letter for the second letter. = 25

We can choose any letter from A to Z except for the first & second letter for the third letter. = 24

We can choose any letter from A to Z except for the first, second & third letters for the fourth letter. = 23

SO;

No of ways in which 4-letter passwords are possible = 26 × 25 × 24 × 23

No of ways in which 4-letter passwords are possible =  358800

he spend 5.1 minutes chatting with his friends.

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5.1

step-by-step explanation:

if you want to separate 54 into 6 individual tiers then you need to divide if you want to separate 54 into 6 individual tiers then you need to divide 6 and 54.

if you divide 9 by 6 you will get 54.

- hope i .