Respuesta :

Answer:

Step-by-step explanation:

The probability of breakdown

Concrete mixer is 1/4, dumper 1/6, and hoist 1/8.

1. All machines breakdown.  

1/4 +1/6 + 1/8 = 13/24

2. 2 machines break down

CM and D 1/4 + 1/6 = 5/12

CM and H 3/8

D and H 7/24