For every 4,240 strings of decorative lights manufactured at a lighting factory, about
480 are considered deficient before the time of packaging and are disposed of.
if 162 strings of lights were disposed of last week because they were deficient, how
many strings of lights were manufactured?

1431 total strings of lights.

Step-by-step explanation:

First, we need to set up a proportion for this problem.

    480 deficient             =             162 deficient  

      4,240 total                                 x total

use the "butterfly" method: multiply each diagonal of the proportion and set them equal to each other.

162 * 4,240  =   480x

686880 =   480x

686880/480 =  x

x = 1431 total strings of lights.

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.