In how many ways can six boys and four girls be arranged in a straight line so that no two girls are ever together.
"\u0421^7_4\u00d76!\u00d74! =\\frac{7!\u00d76!\u00d74!}{4!\u00d73!}=7\\cdot6\\cdot5\\cdot4\\cdot6\\cdot5\\cdot4\\cdot3\\cdot2\\cdot1=604800"
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