B-8 would be the answer. This is because we are saying you have 8 less than something. So no matter what something is, we are taking away 8 from it. Since our something is unknown, we use our variable 'b' in its place, and subtract 8, giving us b-8.<span />
The correct option is : 2
<u><em>Explanation</em></u>
For finding the mean number of working TV sets, we need to <u>divide the total number of TV sets by the total frequency</u>.
Now for finding the total number of TV sets, first we will <u>multiply each number of TV sets by it's frequency and then sum up all the results</u>.
So, the total number of TV sets

and total frequency 
Thus, the mean number of working TV sets 
Answer:
you will need to subtract 15% from $12 and get 10.20 now times that by 5 and you will get $51.