Xiao Ming's money to buy a pen is 5 yuan, Xiao Hong's money to buy a pen is 2 yuan, two people buy a pen more than one yuan, how much is a pen?

Xiao Ming's money to buy a pen is 5 yuan, Xiao Hong's money to buy a pen is 2 yuan, two people buy a pen more than one yuan, how much is a pen?

Suppose a pen costs X Yuan
(X-5)+(X-2)-X=1、
2X-7-X=1
X=1+7
X=8