Question

Alexandra needs to mix cleaning solution in the ratio of 1 part bleach for every 4 parts water. When mixing the solution, Alexandra makes a mistake and mixes in half as much bleach as she ought to have. The total solution consists of 27 mL. How much bleach did Alexandra put into the solution?

• A. $6$ mL
• B. $8$ mL
• C. $7$ mL
• D. $3$ mL

Answer 1

The correct option is D $3$ mL

3 mL: The correct ratio is 1:4, which means that there should be x parts bleach and 4x parts water.However, Alexandra put in half as much bleach as she should have, so she put in $\frac{x}{y}$ parts bleach. You 2 can represent this with an equation:$\frac{x}{2}+4x=27$. Now solve for x:

$x+8x=54$

$9x=54$

$x=6$

You were asked to find how much bleach Alexandra used. This equaled $\frac{x}{2}$, so Alexandra used $\frac{6}{2}=3mL$ of bleach.