HOW OLD WAS BILL GATES WHEN HE BECAME THE RICHEST MAN IN THE UNITED STATES

4. - NGAN HANG CAU HOI K10 HK1NH 2009 2010
NGAN HANG CAU HOI K10 HK1NH 2009 2010
4. How old was Bill Gates when he became the richest man in the United States?A. 34 B. 51 C. 42 D. 44