Answer:
30 gallons solution 4% and 10 gallons solution 8%
Step-by-step explanation:
4x+8y=40•5 and x+y=40
x=40-y
4(40-y)+8y=200
160-4y+8y=200
4y=200-160
4y=40 => y=10 (gallons solution 8%)
=> x=40-10=30 (gallons solution 4%)
30 gallons solution 4% and 10 gallons solution 8%