Sara makes cakes during the five weekdays to sell on weekends. She makes 4 cakes a day and sells her cakes for $8. In 4 weeks she managed to sell all the cakes. How much money did she collect during that time?
During the week she makes 5 days/week * 4 cakes/day = <<5*4=20>>20 cakes.
After selling them over the weekend she earns 20 cakes * $8/cake = $<<20*8=160>>160.
In 4 weeks she raised $160/week * 4 weeks = $<<4*160=640>>640.
#### 640