Problem Solving

On a Saturday night, each of the rooms at a certain motel was rented for either $40 or $60. If 10 of the rooms that were rented for $60 had instead been rented for $40, then the total rent the motel charged for that night would have been reduced by 25 percent. What was the total rent the motel actually charged for that night?
(A) $600
(B) $800
(C) $1,000
(D) $1,600
(E) $2,400

ANS is B

Any ideas how to solve this?

This problem is a bit poorly worded. But here goes:

If the 10 rooms of the total rooms that were rented were rented for 40 bucks instead of 60 then:

600 - 400 = 200

200/x = 25/100

25x = 20,000

x = 800

Thanks!