Brain Teasers
Sneak Thief
A thief has been at work in a classroom. When the pupils return from lunch, 80 percent of them have lost a pencil, 85 percent have lost a pen, 74 percent have lost a ruler, and 68 percent have lost an eraser.
What percentage, at least, must have lost all four items?
What percentage, at least, must have lost all four items?
Answer
If you assume that there are 100 pupils, then adding the percentages together will give the total number of losses: 80+85+74+68=307. This means that there are 3 losses each for each pupil, with 7 pupils losing all 4 items. Therefore, the smallest percentage of pupils that lost all four items is 7%.Hide Answer Show Answer
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