I line that is perpendicular is a line with reversed slopes like 2/1 is perpendicular to -1/2. So find the slope by getting the y by itself and reverse it. Remember to switch the signs too! P.S. if you don't know how to get the y by itself just take and subtract 3x from -5y and -4 then divide by 5. Hope I helped!
1 liters y and 1 liters b since the question states that you need to add
Answer = <span>6 US gallons</span>
According to my calculations it should be 77
