It is known that ABC is an integer that is not zero, 7 / 2 equals 9 / 5 equals 10, only 21, ABC is arranged from small to large

It is known that ABC is an integer that is not zero, 7 / 2 equals 9 / 5 equals 10, only 21, ABC is arranged from small to large

∵(7/2)A=(9/5)B=(21/10)C
Multiply by 10 to get:
35A=18B=21C
The number is inversely proportional to the letter,
∴A<C<B.