Why did Amanda find it especially unusual to find Jeffrey on her street?

On the day that Maniac Magee arrived in town, he went to the East End.  The East End in Two Mills was where almost all of the African American citizens lived.  Amanda Beale, who was black, lived in the East End.  When she saw Maniac Magee, a white kid, on the black side of town, she was both surprised and suspicious.  Amanda wondered to herself, "Who was this white stranger kid!"  It was rare that anyone who was white (the West End was where almost all the white people lived) visited the East End.  He greeted her first.  She let go of her hesitation and suspicion enough to greet him back.

Despite Amanda's initial suspicion, she and Maniac became friends.  They both had something in common.  They were both friendly people.