The mean of 5 numbers is 11. The numbers are in the ratio 1 : 1 : 2 : 3 : 4. Find the numbers.

5, 5, 10, 15, 20

Step-by-step explanation:

Since the mean of the 5 numbers is 11, we know that the sum of the 5 numbers is 5 * 11 = 55. If we call the numbers x, x, 2x, 3x and 4x respectively based off of the ratio, we can write:

x + x + 2x + 3x + 4x = 55

11x = 55

x = 5 so 2x = 2 * 5 = 10, 3x = 3 * 5 = 15 and 4x = 4 * 5 = 20, therefore, the numbers are 5, 5, 10, 15, and 20.

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.