Answer:
21
Step-by-step explanation:
If 7 apples cost y cents, how many can you buy for x dollars?
As y cents buy 7 apples, y dollars will buy 7×100 apples.
Hence one dollar will buy 7×100y=700y apples and,
x dollars will buy 700y × x apples or 700x y apples.
Hence 7 apples multiplied by $6.30 divided by $2.10 will get you 21 apples.
Have a beautiful day! v(⌒o⌒)v♪