(i) How many stores does the distribution company serve?
Total Number of stores = 3+15+26+20+16=80

(ii) What is the most common distance of stores from the company's godown?
For this always see maximum frequency which is 26 in this table/case:
So,
The most common distance of stores from the company's godown is 21 to 30 kilometers (because it has the maximum frequency; 26 stores).

(iii) How many stores are 35 km or more from the godown?
From Table:
There are 16 stores which are 41 km or more from the godown, and 20 stores which are between 31 to 40 km from the godown. From the table we cannot say anything that how many of these 20 stores are 35 km or more from the godown.

(iv) What percentage of stores are 31 km or more from the godown?
There are 20+16=36 stores which are 31 km or more from the godown. Hence, the percentage of these stores is given as,
36/Total no. of stores = 36/80 = 0.45
0.45 x 100%
45%