Question

q2 the table below shows the cost ($) of buying different numbers of notebooks. which equation best describes the relationship between the number of notebooks, n, and the total cost, t?

number of notebooks (n) | 1 | 2 | 3 | 4
total cost (t) | 2 | 4 | 6 | 8

options:

• t = n + 2
• t = 2n + 2
• t = 2n
• t = n²

Explanation:

Step1: Test \( T = n + 2 \)

For \( n = 1 \), \( T = 1 + 2 = 3 \), but table has \( T = 2 \). Not valid.

Step2: Test \( T = 2n + 2 \)

For \( n = 1 \), \( T = 2(1) + 2 = 4 \), table has \( T = 2 \). Not valid.

Step3: Test \( T = 2n \)

For \( n = 1 \), \( T = 2(1) = 2 \) (matches). \( n = 2 \), \( T = 2(2) = 4 \) (matches). \( n = 3 \), \( T = 2(3) = 6 \) (matches). \( n = 4 \), \( T = 2(4) = 8 \) (matches).

Step4: Test \( T = n^2 \)

For \( n = 1 \), \( T = 1^2 = 1 \), table has \( T = 2 \). Not valid.

Answer:

\( T = 2n \) (the option with \( T = 2n \))