A grocery store clerk put only packages of flour tortillas and packages of corn tortillas on a shelf. The ratio of the number of packages of corn tortillas to the total number of packages on the shelf was 7 to 16. Which number could be the number of packages of flour tortillas the clerk put on the shelf?
corn tortillas : total = 7 : 16
but the total consisted of only corn tortillas and flour tortillas,
so flour tortillas : corn tortillas had to be 9 : 7
take it from there.