A toy shop stocked only building-set boxes and puzzle boxes. In November, the shop had 360 building-set boxes, and the rest were puzzle boxes. In February, the number of building-set boxes increased by 25%, while the number of puzzle boxes decreased by 40%. The total number of boxes remained the same. How many puzzle boxes did the shop have in November?
- 225 boxes
- 270 boxes
- 450 boxes
- 144 boxes
Need a hint?
Because the total number of boxes stayed the same, how many boxes were gained must equal how many boxes were lost.
Worked answer
- Increase in building-set boxes = 25% × 360 = 90 boxes.
- Since the total stayed the same, the decrease in puzzle boxes was also 90 boxes.
- The 90-box decrease was 40% of the original number of puzzle boxes.
- Original number of puzzle boxes = 90 ÷ 40% = 225.
- Answer: 225 boxes.
The mistake this question tests
Stopped at one part in ratio
Comparing 25% and 40% directly is not enough. The 25% is based on 360 boxes, while the 40% is based on the unknown number of puzzle boxes, so the actual numbers gained and lost must be equated.
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