Respuesta :

olemakpadu
The machine can produce 22 400 copies in 7 hours.

In 7 hours    22 400 copies were produced.

In 1 hour                                 22 4000/ 7    would be produced.

Therefore in 21 hours        (22 400 / 7) * 21 will be produced.

Solving this  =      22 400 * 3.           

                       =       67 200  copies.