1 ) 4 d i ff ere n t m o d e l s , 3 d i ff ere n t co l ors an d 2 s i zes 4 ⋅ 3 ⋅ 2 = 24 ( c h o i ces ) 17. 20 e n t r i es in t h e c h ess t o u r nam . 20 − t h e n u mb er o f w a ys t o se l ec t 1. pl a ces 19 − t h e n u mb er o f w a ys t o se l ec t 2. pl a ces 18 − t h e n u mb er o f w a ys t o se l ec t 3. pl a ces t h e n u mb er o f w a ys t o se l ec t t h e t o p t h ree = 20 ⋅ 19 ⋅ 18 = 6 , 840
The total number of choices for one car is 24, which corresponds to option D. For the chess tournament, the total number of ways the 20 participants can finish in first, second, and third places is 6,840, which corresponds to option B.
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