The question asks to calculate the maximum possible percentage error in the amount of cream due to Emma's assumption that the measurement is exact.

Step 1: Understand the rounding range

• The cream's quantity is given as 150 ml to the nearest milliliter.
• Since it's rounded to the nearest milliliter, the actual quantity of cream could be anywhere between 149.5 ml and 150.5 ml.

Step 2: Calculate the possible error

The error is the difference between the assumed value (150 ml) and the extreme actual values:

• Maximum error = 0.5 ml (this is the difference between 150 ml and either 150.5 ml or 149.5 ml).

Step 3: Calculate the percentage error

The percentage error is calculated as:

$\text{Percentage error} = \left( \frac{\text{Maximum error}}{\text{Measured value}} \right) \times 100$

Substitute the values: $\text{Percentage error} = \left( \frac{0.5}{150} \right) \times 100$

Now, let's compute that.The maximum possible percentage error is approximately 0.33% due to Emma's assumption that the measurement is exact.

Would you like further details or clarification? Here are 5 questions related to this topic:

1. How is rounding related to percentage error?
2. What happens if the measurement precision changes (e.g., rounding to the nearest 0.1 ml)?
3. How can Emma minimize the percentage error in future measurements?
4. Why is understanding percentage error important in practical measurements?
5. Can percentage error increase if more assumptions are made?

Tip: Always consider both the upper and lower bounds when calculating potential errors in measurements.