According to D3665, what is used to calculate the sampling point length?

The correct answer is based on the guidelines outlined in D3665, which pertains to the sampling of aggregates. In this context, the sampling point length is calculated using the formula l(n) x l, where l(n) represents a designated length per sample and l signifies the total sampling length. This relationship helps ensure that the sampling process yields a representative portion of the material being tested.

Using this formula allows inspectors to systematically determine the appropriate sampling lengths based on the characteristics of the aggregate material. It simplifies the process of ensuring that the sampled quantity is both adequate and representative of the lot being assessed, adhering to standardized practices that promote consistency across samples.

Other choices do not accurately represent the correct calculation for determining sampling point length. For example, using 'w' (weight) in other options does not relate to the length measurement necessary for establishing sampling points, and additions like 'n + l' or subtractions such as 'l - w' do not align with the direct requirements set forth in the D3665 standard for quantitative sampling measurements.