document.write( "Question 972737: Roy must elect 3 courses from among 6 courses in group I and 3 courses in group II. If he must take at least 1 of his 3 electives from each group, how many choices does he have? (Hint: First find how many choices he has if he elects only 1 course from group I. Then find how many choices he has if he elects 2 courses from group I. Since he must do one or the other of these, the final answer is the sum of the two answers.) \n" ); document.write( "
Algebra.Com's Answer #595445 by Edwin McCravy(20054)\"\" \"About 
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Roy must elect 3 courses from among 6 courses in group I and 3 courses in group
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document.write( "Case 1:\r\n" );
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document.write( "We find how many choices he has if he elects exactly 1 course from group I. \r\n" );
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document.write( "A.  6 courses Choose 1 = 6C1 = 6 ways\r\n" );
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document.write( "then for each of those 6 ways to choose 1 from group I, from group II, there are\r\n" );
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document.write( "B.  3 courses Choose 2 = 3C2 = \"3%2A2%2F%282%2A1%29=6%2F2\" = 3 ways\r\n" );
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document.write( "to choose 2 courses from group II.\r\n" );
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document.write( "That's 6×3 = 18 ways for case 1.\r\n" );
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document.write( "Case 2:\r\n" );
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document.write( "We find how many choices he has if he elects exactly 2 courses from group I. \r\n" );
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document.write( "A.  6 courses Choose 2 = 6C2 = \"6%2A5%2F%282%2A1%29=30%2F2\" = 15 ways\r\n" );
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document.write( "then for each of those 15 ways to choose 2 from group I, from group II there are\r\n" );
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document.write( "B.  3 courses Choose 1 = 3C1 = 3 ways\r\n" );
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document.write( "to choose 1 courses from group II.\r\n" );
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document.write( "That's 15×3 = 45 ways for case 1.\r\n" );
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\n" ); document.write( "the sum of the two answers.
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document.write( "18 + 45 = 63 ways total.\r\n" );
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document.write( "Edwin
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