Question 976297
We can substitute a number, do the math, then find the ratios.

Say Amanda has 12 books. 3/4 of that, 9 is 1/6 of Balas's so Bala has 54, and Calvin has 27.

B:C:A is 54:27:9 which are all multiples of 9 so we reduce to 6:3:1 as the ratio.