Answer:
67%
Step-by-step explanation:
Let the percentage of the first solution = x
7 gallons + 4 gallons = 11 gallons
Our system of equation is
Seven gallons of a sugar solution was mixed with 4 gallons of a 80 percent sugar solution to make an 72 percent sugar solution.
7 gallons × x % + 4 gallons × 80% = 72% × 11 gallons
= 7x + 3.2 = 7.92
Collect like terms
7x = 7.92 - 3.2
7x = 4.72
x = 4.72/7
x = 0.6742857143
Converting to percentage
0.6742857143 × 100
= 67.42857143%
Approximately, the percent concentration of the first solution is 67%
