Answer:
6.1 gallons of 100% antifreeze and 48.9 gallons of 10% antifreeze
Explanation:
Let the amount of 100% antifreeze be x gallon
let the amount of 10% antifreeze be y gallon
total amount to drum = 55 gallons
therefore x + y = 55 -------------------------------Eqn 1
100%(x) + 10(y) = 20%(55)
x + 0.1y = 11--------------------------------------Eqn 2
Both equations are solved simultaneously
From eqn 1 x = 55-y
Substitute x = 55-y into eqn 2
55-y+0.1y = 11
collecting like terms
44 = 0.9y
y = 48.88889
x = 55- 48.88889 = 6.11111 gallons
Therefore 6.1 gallons of 100% antifreeze and 48.9 gallons of 10% antifreeze