Let's use the method of setting up a system of equations to solve this problem.
Let x be the number of pints of the first type of fruit drink (30% pure), and y be the number of pints of the second type of fruit drink (55% pure). We want to find the values of x and y that will produce 60 pints of a mixture that is 40% pure.
We can start by setting up two equations based on the information given:
Equation 1: x + y = 60 (since we want to produce 60 pints of the mixture)
Equation 2: 0.3x + 0.55y = 0.4(60) (since we want the mixture to be 40% pure)
Simplifying Equation 2, we get:
0.3x + 0.55y = 24
Now we have a system of two equations with two unknowns:
x + y = 60
0.3x + 0.55y = 24
We can solve this system using substitution or elimination. Here, we'll use substitution:
Solving Equation 1 for x, we get x = 60 - y. Substituting this expression for x in Equation 2, we get:
0.3(60 - y) + 0.55y = 24
Expanding and simplifying, we get:
18 - 0.3y + 0.55y = 24
Combining like terms, we get:
0.25y = 6
Dividing by 0.25, we get:
y = 24
Substituting this value of y back into x + y = 60, we get:
x + 24 = 60
Solving for x, we get:
x = 36
Therefore, we need 36 pints of the 30% pure fruit drink and 24 pints of the 55% pure fruit drink to make 60 pints of a mixture that is 40% pure.