When you do 11^7 divided by 11^4 you get:
1331
Find the total square footage of each room. The room will be a rectangle and finding the area of a rectangle is just the length times the width
area of rectangle = lw
area of each room = 14 x 20.5 = 287 ft^2
The 4 rooms each have the same square footage.
Total square footage of all rooms = 287 x 4 = 1148 ft^2
To find how many roles of carpet are needed, divide the footage needed to be covered by the footage per carpet
1148/200 = 5.74
You can't buy 5.74 of a carpet roll, so you will need 6 rolls :)
Hope I helped
With the given information you can form a system of equations with the help of the formular for the nth term of an arithmetic sequence. From which you find the first term and the common difference, with which you can wite the recursive formula for the sequence.
There are 56 minutes for 10 people to paint 7 walls!