Answer:
Approximately 143 mL of 1:4 solution and 457 mL of water
Explanation:
A 1:4 solution has a concentration of 1/(1+4) = 1/5 or 20%.
Similarly, a 1:20 solution has a concentration of 1/(1+20) = 1/21 or 4.76%.
If x is the mL of 20% solution and y is the mL of water, then:
x + y = 600
1/5 x = 1/21 (600)
Solve:
x = 5/21 (600)
x ≈ 143
y ≈ 457
You need approximately 143 mL of 1:4 solution and 457 mL of water.