Answer:
mega mind<3<3<3<3<3<3<×<×<3<3<×
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 
You can simplify the fraction to get 2/5. If you convert this into a decimal you will get 0.4, so D is your answer.
12q+3r=15
-4q-4r=-44
-4q=-44+4r
q=11-r
12(11-r)+3r=15
132-12r+3r=15
132-9r=15
117=9r
r=13
-4q-4(13)=-44
-4q-52=-44
-4q=8
q=-2