Ben and Blake both love to collect baseball cards. The ratio of cards that Ben has compared to the number that Blake has is 2:3. If Blake buys 500 more cards, he will have 3800 cards. How many cards does Ben currently own?

I'm terrible at math any here is appreciated.

Use sigma notation to represent the following series for 9 terms.

Marquise has 200 meters of fencing to build a rectangular garden. the garden's area (in square meters) as a function of the garden's width w w (in meters) is modeled by: a ( w ) = − w 2 + 1 0 0 w a(w)=−w 2 +100w what side width will produce the maximum garden area? meters