P shows the way a T-shirt is folded. Q shows the image of ink spilled over such a folded T-shirt. If the T shirt is unfolded and viewed from behind, which image most accurately represents the ink stain?
Show Hint
In folding problems, identify the axis of symmetry. Any pattern applied across a fold will be mirrored on the other side when unfolded. Remember to consider the final viewing perspective (front vs. back).
Since the fold runs straight down the middle and the stain pattern itself is left-right symmetric, the pattern that shows up on the back ends up looking the same as the pattern on the front, just as if the shirt were see-through.
The front view after unfolding would show the original stain plus its mirrored copy sitting side by side across the centre crease.
Because ink soaks straight through the fabric layers, the exact same pair of mirrored stains shows up on the back too, which is what Option B shows.
So Option B, not a four-stain or an uneven pattern, is what appears on the reverse side.
Was this answer helpful?
0
Show Solution
Approach Solution -2
Another way to check this is to track just one drop of ink at a single point on the folded shirt, rather than the whole splatter pattern at once.
Option A: places that tracked point correctly for the front view but is being checked against the back view, so it answers the wrong side of the shirt.
Option B: places the tracked point and its mirrored twin at the positions a single vertical fold would put them once the shirt is opened and turned over, which is consistent with how ink transfers straight through the layers.
Option C: would need the point to also duplicate top to bottom, which only happens if there were a second, horizontal fold, and no such fold is shown here.
Option D: loses the mirror symmetry between the point and its twin, which cannot happen since both sides of the stain come from the same single crease.
Only Option B keeps the tracked point and its mirror twin exactly where a single vertical fold, viewed from behind, would put them.
