We have that
x+4y<12
y<3
using a graph tool
see the attached figure
the solution in the attached figure
It can hold 9 ounces of oil and 90 ounces of gasoline cause if you take 10 oz of gas and times it by 9 it equals 90 and if you take 1 oz of oil and times it by 9 it equals 9 then take 90+9=99
400 = 45x + 30x
400 = 75x
5.333 = x
Lets test
45mph for 5.333 hours = 240 miles
30mph for 5.333 hours = 160 miles
240 + 160 = 400 miles apart.
It will take him 2 hours to make the recipe-- start to finish
hope this helps, Mandy! :-)