Eduardo spent $34 on a magazine and some candy bars if the magazine cost $6 and each candy bar cost $4 then how many candy bars did he buy

7 candy bars

Step-by-step explanation:

First we need to subtract the cost of the magazine from the total cost

$34-$6=$28

Now the $28 that remains is the cost of all the candy bars, so if we divide by the price, we will get  the amount.

$28/$4=7 candy bars

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.