In a school gym, the ratio of the number of boys to the number of girls was 4: 3. after 160 boys left the gym, the ratio became 4: 5. how many girls were there in the gym?

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.