ATI TEAS (Test of Essential Academic Skills) Version 7MathematicsMedium
A medical laboratory technician is preparing a solution by mixing 3 parts of concentrate with 7 parts of diluent. If the total volume of the solution needs to be 250 mL, how much concentrate is required?
- A100 mL
- B25 mL
- C50 mL
- D75 mL
Show answer & explanationAnswer & explanation
Correct answer: D. 75 mL
The ratio of concentrate to diluent is 3:7, meaning there are 3+7 = 10 total parts. The concentrate makes up 3/10 of the total solution. To find the amount of concentrate needed, calculate (3/10) * 250 mL = 75 mL.
Why the other options are wrong
- A. This would be the amount if the ratio was 4:6, making 4/10 of the total.
- B. This would be the amount if the ratio was 1:9, making 1/10 of the total.
- C. This would be the amount if the ratio was 2:8, making 2/10 of the total.
Ratio Proportion Calculation
Determining the quantity of a component within a mixture based on a given ratio and total volume.
- Ratios represent parts of a whole.
- Summing ratio parts gives the total number of parts.
- Each part's proportion is its ratio value divided by the total parts.
Memory trick: Parts add up, then proportion to the Whole!