Question

1. error analysis describe the error. if p = -5.8, t has a weight 3 times u and u has a weight of 2. what is the weight of v?

number line: -10, -8 (t), -6, -4, -2 (u), -1 (v), 0, 2

\\(\frac{3(-8)+2(-3)+w(-2)}{3+2+w} = -5.8\\) student’s work with red x: steps including “-30 - 2w = -5.8(5 + w)”, “-30 - 2w = -29 - 5.8w”, “3.8w = 1”, “w = 0.3”

\\(\circ\\) the student used the wrong weight for t. the weight should be 6 if t has a weight 3 times u and u has a weight of 2. \\(t = 2 \times 3 = 6\\).
\\(\circ\\) the student used the wrong weight for u. the weight should be 6 if t has a weight 3 times u and u has a weight of 2. \\(u = 2 \times 3 = 6\\).
\\(\circ\\) the student used the wrong weight for t. the weight should be 5 if t has a weight 3 times u and u has a weight of 2. \\(t = 2 + 3 = 5\\).
\\(\circ\\) the student used the wrong weight for u. the weight should be 5 if t has a weight 3 times u and u has a weight of 2. \\(u = 2 + 3 = 5\\).

Explanation:

We need to find the error in the student's calculation. Given that T has a weight 3 times U, and U has a weight of 2. So the weight of T should be \( 3\times2 = 6 \), not -8 (or the weight used in the student's formula). Let's check each option:

• Option 1: Says the student used the wrong weight for T, and T should be \( 2\times3 = 6 \). This matches our calculation.
• Option 2: Claims U's weight is wrong, but U's weight is given as 2, so this is incorrect.
• Option 3: Says T's weight should be 5, but \( 3\times2 = 6 \), not 5. Incorrect.
• Option 4: Claims U's weight is wrong, but U's weight is 2, so incorrect.

Answer:

A. The student used the wrong weight for \( T \). The weight should be 6 if \( T \) has a weight 3 times \( U \) and \( U \) has a weight of 2. \( T = 2 \times 3 = 6 \).