To determine whether Jerome's brother is correct, we need to analyze the ratios involved when increasing the amount of water and drink mix.
Original Ratios
Jerome's original mixture contains:
- Water: 8 cups
- Drink mix: 3 cups
Part-to-Part Ratio of Water to Drink Mix: The ratio of water to drink mix can be represented as: \[ \text{Water:Drink Mix} = 8:3 \]
Part-to-Whole Ratio of the Mixture: The total mixture consists of both water and drink mix: \[ \text{Total} = 8 \text{ cups (water)} + 3 \text{ cups (drink mix)} = 11 \text{ cups (total)} \] The part-to-whole ratio (water to total) is: \[ \text{Water:Total} = 8:11 \] And for drink mix to total: \[ \text{Drink Mix:Total} = 3:11 \]
Analyzing Jerome's Brother's Method
Jerome's brother suggests adding one cup of water for every one cup of drink mix added. This means that if Jerome adds \( x \) cups of drink mix, he will also add \( x \) cups of water. Let's analyze:
Assuming Jerome adds \( y \) cups of drink mix:
- Water: \( 8 + y \)
- Drink Mix: \( 3 + y \)
The new ratio of water to drink mix would be: \[ \text{New ratio} = \frac{8 + y}{3 + y} \] To analyze whether this maintains the original ratio of \( \frac{8}{3} \), let's set up a proportion: \[ \frac{8 + y}{3 + y} = \frac{8}{3} \]
By cross-multiplying: \[ 3(8 + y) = 8(3 + y) \] Expanding both sides: \[ 24 + 3y = 24 + 8y \] Subtracting \( 3y \) from both sides gives: \[ 24 = 24 + 5y \] Then, \[ 0 = 5y \] This means \( y = 0 \) is the only solution. Therefore, the ratios do not remain equivalent or the same if we increase the amounts as Jerome's brother suggests.
Conclusion
Jerome’s brother is not correct. When he suggests adding 1 cup of water for every 1 cup of drink mix, while he tries to keep the amount of drink mix proportional, he disrupts the original ratio of water to drink mix \( (8:3) \). The correct approach to keep the ratio the same when increasing the amounts is to multiply both parts of the mixture by the same factor, which is what Jerome’s sister recommends.
Thus, the analysis demonstrates that the only way to maintain the \( 8:3 \) ratio is to multiply the initial amounts by some common factor (for example, multiplying both by 2 or 3, etc.), rather than changing both amounts in a fixed addition form.