Answer:
See below for answer
Step-by-step explanation:
Set up the equation 5x+7x+9x=2100 and solve for x:
5x+7x+9x=2100
21x=2100
x=100
Now multiply the proportion by 100:
5:7:9 * 100 = 500:700:900
This means that Antony will get $500, Terry will get $700, and Jack will get $900.
