Ethan bought some chips and pop for his class party. He bought a total of 29 items. Each bag of chips cost $0.79 and each bottle of
pop cost $2.29. He spent a total of $36.41. How many bags of
chips did he buy?

the given 6 = w/p is equivalent to 6p = w, where w is the total area of the walls and p is the area covered by a single can of paint.

knowing that 6 cans of paint will be needed, 6p = w becomes 6(6) = w = 36.   this tells us that the total area to be painted is 36 square units.