Question

Shown on the left are three types of pencils A, B, C (distinguished by the thickness of the two dark side-bands). In the barcode-like bundle on the right, pencils point either up or down. Find the total number of type A pencils. 

Hint:

When multiple similar items must be counted, reduce the identification to a single unmistakable visual cue (here, thick–thin edges) and ignore features (like up/down) that don’t affect the classification.

Answer 1

Classify by edge-band thickness:
Type A: one thick dark band on one side and one thin dark band on the other side (thick–thin).
Type B: both dark bands are thin (thin–thin).
Type C: both dark bands are thick (thick–thick).
Note that pointing up or down does not change left–right band thickness, so orientation is irrelevant to the type.
[4pt] Count:
Scan each vertical pencil in the bundle and mark those with the thick–thin signature.
Exactly 7 pencils match Type A, so the answer is \(\boxed{7}\).