Answer:
28
Explanation:
To solve this, I would first add up the total of the numbers in the ratio.
9 + 7 + 2 = 18
Then, I would divide 72 by that number.
72/18 = 4.
Finally, I would multiply that quotient by 7 because 7 is the number in the ratio for B's.
4 x 7 = 28