A new department store needs a new rectangular parking lot to encompass the store. The front of the department store is 200 feet wide and the store is 100 feet deep. The front of the store faces north. The contractor wants the width of the parking lot on the south and east sides of the store to be the same. Also, the width of the parking lot on the north side is to be 8 times as wide as the south and the width of the parking lot on the west side is to be 10 times as wide as the east. When completed, the parking lot will be 38,900 square feet of blacktop. How wide is the west parking lot?