Playing with toy alphabet blocks, Dani mixes four of the ABCDE blocks into some combination (doesn't care about the order.) Then she takes the XYZ blocks and carefully puts these into a specific order. How many different outcomes are possible for this arrangement of seven blocks?

The total outcomes that are possible for this arrangement of seven blocks are 5C4 * 4! * 3!

Step-by-step explanation:

Given

Out of five blocks i.e ABCDE, four blocks need to be drawn.

Hence the possible ways of drawing four blocks out of total set of 5 blocks is

5C4

Now, the total number of ways of arranging these selected four blocks is 4!

The total number of ways of arranging three blocks is 3!

Hence, the total outcomes that are possible for this arrangement of seven blocks are 5C4 * 4! * 3!

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.