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There are four different white balsl and four different black balls. The number of ways that balls can be arranged in a row so that white and black balls are placed alternately is_____A. `(4!)^(2)`B. `2(4!)^(2)`C. `4!`D. `(4!)^(3)` |
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Answer» We have to arrange 4 different white balls and 4 different balck balls as shown below (i) WB WB WB WB (ii) BW BW BW BW This can be done in `4!xx4!+4!+4!xx4!` ways, i.e., `2(4!)^(2)`. |
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