Respuesta :

1 hour:
2 2/5  /  7/12
= 12/5  /  7/12
= 12/5 x 12/7
= 144/35
= 4 4/35 

answer
4 4/35 miles per hour
this would be  2 2 /5 / 7/12

 = 12/5 / 7/12

= 12/5  * 12/7  =  144/35  = 4 4/35  hours answer