Answer: 4 × 5 × 6 = 120
Explanation:
1) This is a direct use of the counting principle, which states that the number of different ways a combination of independent events can happen is equal to the product of the number of different outcomes for each event.
That is, if event A can have m different outcomes, event B can have n different outcomes, and event C can have p different outcomes, the total number of different combinations is m × n × p.
2) In this case, the lawyer can use 4 different pais of pants, 5 different shirts, and 6 different ties, so the number of different combinations of the three items is: 4 × 5 × 6 = 120.
3) You can see that if you make a diagram (may be a tree diagram).
With that you can see that each pair of pants, can go with 5 shirts, which make 4 × 5 different couples of pants - shirts. After that, each different couple of pants - shirts can go with 6 different ties, so you have 4 × 5 × 6 three-piece combinations.
First you plug in the information you already know. 163.5= 
Now you have to solve for the mass so you multiply 0.492 by 163.5 
Lastly, you simplify and you will get 80.44. Hope this helped :)