contestada

Bj can overhaul a​ boat's diesel inboard engine in 15 hours. his apprentice takes 30 hours to do the same job. how long would it take them working together assuming no gain or loss in​ efficiency?

Respuesta :

BJ rate: 1/20 job/hh
----
App rate: 1/60 job/hr
---
Together rate: 1/x job/hr

Equation:
rate + rate = together rate

1/20 + 1/60 = 1/x

Multiply thru by 60x
3x + x = 60
4x = 60
x = 15 hrs (time to do the job together)

Otras preguntas