Question 1076603
7R+2P=4500
The 7:2 ratio adds to 9,and 5 times 9 is 45.
Therefore, 35:10 is the same ratio and 3500:1000 is also the same ratio, which adds to 4500.
3500 gallons of regular at 1000 gallons of premium.

System:
Reg+Premium=total
Reg=(7/2)P