I've got a gallon (actually more but to keep it simple we'll say a gallon) of fuel that is mixed with oil for a 24:1 mixture. If one needed to make this fuel a 40:1 mixture how much fresh gas (no oil) would you add to make it a 40:1 mixture?

Some facts for mixing a gallon:

a 24:1 mixture requires 5.3 ounces of oil

a 40:1 mixture requires 3.2 ounces of oil

In other words what would be the ratio of premixed 24:1 gas/oil together with plain gas to get a ratio of 40:1.

Thanks in advance for your input.