A bowl contains 20 ounces of water. When the bowl is uncovered, the amount of water in the bowl decreases...

1. TRANSLATE the problem information

• Given information:
  • Bowl starts with 20 ounces of water
  • Currently has 9 ounces of water
  • Water decreases by 1 ounce every 4 days
  • Need to find: number of days uncovered

2. INFER what happened and the approach

• First, I need to find how much water was lost:
  Water lost = Starting amount - Remaining amount = \(20 - 9 = 11\) ounces
• The rate of loss is 1 ounce every 4 days, which means \(\frac{1}{4}\) ounce per day
• Strategy: Use the rate formula (Rate × Time = Amount) to find the time

3. TRANSLATE the rate into mathematical form

• '1 ounce every 4 days' = \(\frac{1}{4}\) ounce per day

4. SIMPLIFY using the rate equation

• Set up the equation: Rate × Time = Amount lost
• \(\frac{1}{4} \times \mathrm{t} = 11\)
• Solve for t: \(\mathrm{t} = 11 \times 4 = 44\)

Answer: D. 44

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak TRANSLATE reasoning: Students misunderstand what the problem is asking for or confuse the given information. They might try to work directly with the 9 ounces remaining instead of first calculating how much water was lost.

This leads to setting up incorrect equations like \(\frac{1}{4}\mathrm{t} = 9\), which gives \(\mathrm{t} = 36\). This may lead them to select Choice C (36).

Second Most Common Error:

Poor INFER skill: Students recognize they need to find the amount lost but struggle with setting up the rate relationship correctly. They might think '1 ounce every 4 days' means they should divide by 1 instead of multiply by 4, or they get confused about the direction of the calculation.

This leads to confusion and random answer selection among the remaining choices.

The Bottom Line:

This problem requires careful reading to understand that you're looking for total time, not rate, and that you must first calculate the total amount of change before applying the rate formula. The key insight is recognizing that 'decreases by 1 ounce every 4 days' establishes a rate that can be used with the total amount lost.