Proportions
Lee makes a mix of fruit punch consisting of
3.5 gallons of liquid fruit punch concentrate with 3 gallons of water to make a total of 6.5 gallons of fruit punch.
The proportion of concentrate to the total fruit punch is 3.5/6.5.
If Lee wanted to make 32.5 gallons of fruit punch, he would need
32.5 * 3.5 / 6.5= 17.5 gallons of concentrate.
Lee would need 17.5 gallons of fruit punch concentrate