There are 72 boys and 90 girls on the math team. for the next math competition, mr. johnson would like to arrange all of the students in equal rows only girls or boys in each tow. what is the greatest number of student that can be in each row

Answer is 18 If you know your division you just divide then you will see that you find something common that answer would be 18 also to get this answer i used GCF
 First what i did was find out what the factors of 72 then i look at the factors of 90