Answer:
20
Step-by-step explanation:

Step-by-step explanation:
Decimal system, also called Hindu-Arabic number system or Arabic number system, in mathematics, positional numeral system employing 10 as the base and requiring 10 different numerals, the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
With each gallon you need 11 gallons with 2 parts red 9 parts yellow and since 11x4= 44 you need to do this 4 times
4x2(red)= 8
4x9(yellow)=36
36+8=44
basically 8 gallons of red
i hope this made sense