1. Forty-five students in a PE class were asked to walk around the oval for 10 minutes. The distances (in meters) covered by the students within this period are shown in the following frequency distribution table:

Distance (in meters):
1. 501-700
2. 701-900
3 .901-1,100
4. 1,101-1,300
5. 1,301-1,500
Number of Students:

In number 1. 7
2. 9
3. 13.
4. 11
5. 5

a. How many students walked at most 700 meters?
b. How many students walked more than 1,100?
c. How many students walked at least 500 meters?
d. If the distances covered by the students were arranged in increasing order, in which interval could the middle distance be found?