ATI TEAS (Test of Essential Academic Skills) Version 7MathematicsMedium
A patient's blood glucose level was 180 mg/dL. After administering insulin, the level dropped by 25% after 1 hour. What is the patient's blood glucose level after 1 hour, rounded to the nearest whole number?
- A120 mg/dL
- B150 mg/dL
- C135 mg/dL
- D145 mg/dL
Show answer & explanationAnswer & explanation
Correct answer: C. 135 mg/dL
To find the new level, first calculate the amount of decrease: 25% of 180 mg/dL = 0.25 * 180 = 45 mg/dL. Then, subtract this decrease from the initial level: 180 mg/dL - 45 mg/dL = 135 mg/dL. Alternatively, if a value decreases by 25%, it retains 100% - 25% = 75% of its original value. So, 0.75 * 180 = 135 mg/dL.
Why the other options are wrong
- A. This answer suggests a larger decrease than 25%, possibly 33% or miscalculation.
- B. This answer suggests a 16.6% decrease, not 25%.
- D. This answer might be a result of a small calculation error or rounding during intermediate steps.
Percentage Decrease Calculation
Calculating the new value of a quantity after it has been reduced by a specific percentage.
- Calculate the amount of decrease: Percentage * Original Value.
- Subtract the decrease from the original value: Original - Decrease.
- Alternatively, multiply Original Value by (1 - Percentage as decimal).
Memory trick: Find the percent of the whole, then subtract it from the whole goal.