How many different 4-digit sequences can be formed using the digits 0, 6 if repetition of digits is allowed? a. 1296 c. 24 b. 20 d. 2401

The correct option is d.

Step-by-step explanation:

We have to find the number of different ways to form 4-digit sequence using the digits 0, 1,..., 6 if repetition of digits is allowed.

Total digits that can be used are 0,1,2,3,4,5,6. Number of digits is 7.

First place of 4-digit sequences can be formed by 7 different ways.

Similarly, second, third and fourth place of 4-digit sequences can be formed by 7 different ways because repetition of digits is allowed.

So, the number of different ways to form 4-digit sequence using the digits 0, 1,..., 6 if repetition of digits is allowed is

Therefore the correct option is d.

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

4

step-by-step explanation:

im pretty sure it's 4 beacsue 8/2 equals 4