Which is the probability of a crew being selected for a safety audit?

 

Please show your work

1. The lower explosive limit (LEL) of xylene is 1%.

 

In a room where xylene solution is being sprayed, an engineer uses a calibrate combustible gas meter to determine that the xylene concentration is 10% of the LEL.

 

What is the concentration of xylene in this room?

1. 1,000 parts per million (ppm)
2. 10,000 parts per million (ppm)
3. 9% great that the LEL of xylene
4. 11% greater than the LEL of xylene

 

2. What is the flow rate of air moving through a portable blowers with a velocity of 120 FT/Min (3.048 m/min), through ha pipe of diameter 10 inches (25.4 cm)
   1. 425 ft3/min (o.0120 m3/min)
   2. 7 ft3/min (0.198 m3/min)
   3. 54 ft3/min (1.53 m3/min)
   4. 9,420 ft3/min (267 m3/min)

 

3. An operator is working on a piece of machinery that is producing noise at 105 DBA. The company threshold level is at 85 DBA with 5 DBA exchange rate. The local authority is 90 DBA with 3 DBA exchange rate.

How long can this operator be exposed without any control and still respect both limits?

1. Less than 5 minutes
2. 15 minutes
3. 30 minutes
4. 1 hour

 

4. A company has decided to perform one random safety audit monthly of their 10 crews. The following are near miss points the crews accrued over the last year.

Crew 1 = 55

Crew 2 = 30

Crew 3 = 56

Crew 4 = 40

Crew 5 = 45

Crew 6 = 25

Crew 7 = 28

Crew 8 = 49

Crew 9 = 40

Crew 10 = 32

 

A crew is considered to be eligible for the safety audit if it accrued near miss points higher than 40

Which is the probability of a crew being selected for a safety audit?