| A detective under orders to watch a certain back street and count the people who visited a small shop there, bought two raincoats, two jackets, and several hats, because he wanted to avoid drawing attention and so planned to change his clothes frequently while standing at his point of observation. As he began to watch two people went in . One came out. Two more went in, and then three came out. Now four went in, and again three came out. How many people were in the shop at this moment? |
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| 19 |