一道没看懂的数学题。。。。。。

msufcufou

A rectangular floor is covered by a rug except for a strip p meters wide along each of the four edges. If the floor is m meters by n meters, what is the area of the rug, in square meters?
(A) mn – p (m + n)
(B) mn – 2p(m +n)
(C) mn – p2

(D) (m - p)(n - p)
(E) (m –2p)(n – 2p)
没看懂那个毯子是如何放置的？？请大家帮忙解释下。。谢谢！！

rudder86

E 吧。
就是一个长方形，里面在放一个长方形，两个长方形的每条边间距都是p。

IMARCUS

E啊。。就是大长方形套小长方形，中间间隔是p,所以小长方形就是长m-2p宽n-2p