In what proportion should you mix 7% and 1% solutions to get 4% solution?
To determine the proportion, let's assume that we want to mix x% of the 7% solution and (1-x)% of the 1% solution to obtain a 4% solution.
In the 7% solution, we have 0.07x amount of solute (0.07 is the decimal form of 7%) and in the 1% solution, we have 0.01(1-x) amount of solute (0.01 is the decimal form of 1%).
To find the proportion, we need to establish the equation:
0.07x + 0.01(1-x) = 0.04
Let's solve this equation:
0.07x + 0.01 - 0.01x = 0.04
0.06x + 0.01 = 0.04
0.06x = 0.04 - 0.01
0.06x = 0.03
x = 0.03 / 0.06
x = 0.5
So, we need to mix the 7% solution and the 1% solution in a proportion of 0.5 (or 50%): 50% of the 7% solution and 50% of the 1% solution to obtain a 4% solution.