Question

Find the correct choice. (The value equals the number of line intersections.)
Given: a grid with 3 vertical and 3 horizontal lines equals 9; a single vertical crossing a single horizontal equals 1; find the value of the last figure.

• A. 5
• B. 8
• C. 4
• D. None of these

Hint:

When symbols of parallel lines are involved, a common hidden rule is: \(\text{value}=\#\text{vertical}\times\#\text{horizontal}\) (the count of their intersection points).

Answer 1

The Correct Option is C

Rule inference from examples.
- First figure: \(3\) vertical $\times$ \(3\) horizontal $\Rightarrow 3\cdot3=\mathbf{9}\) intersections (matches the given 9).
- Second figure: \(1\) vertical $\times$ \(1\) horizontal $\Rightarrow 1\cdot1=\mathbf{1}\) intersection (matches the given 1).
[2mm] Apply to the asked figure.
In the last figure there are \(2\) vertical lines and \(2\) horizontal lines, so the number of intersections is \[ 2\times 2=\boxed{4}. \]