Final answer:
The correct answer is "a. 2", indicating that for every additional extension of '2 feet or less' of the track, one more support is required.
Step-by-step explanation:
The student's question relates to determining the necessary interval of support installation for a track, given that one additional support is required for every extension of a certain length. To solve this, we consider several lengths: a line of one foot, a line of two feet, a line of three feet, a line of four feet, a line of five feet, a line of six feet, a line of seven feet, and a line of eight feet. However, these options are provided for context, and the actual question does not require deep mathematical computations or comparisons but rather looks for a specific value from the provided choices.
The correct choice is a. 2 because the question specifies that for every extension of track "2 feet or less," an additional support is necessary. This means if more than 4 feet of track is needed, one support is added for the first 4 feet, and one additional support will be required for every subsequent 2-foot section (or part thereof).
If we were to apply this to a practical example:
- For a 5-foot track, you would need 3 supports (one for the initial 4 feet and one more because we have exceeded 4 feet by 1 foot).
- For a 6-foot track, you would need 3 supports (still one for the initial 4 feet and just one additional for the extra 2 feet).
- For a 7-foot track, you would need 4 supports (one for the initial 4 feet and two more because we have an extension beyond 6 feet).