Question
A man has 15 friends out of which 7 are his relatives.
In how many ways can he invite his 9 friends in which at least 5 must be his relatives?Solution
relatives =7, not relatives = 15-7=8 You must invite 9 friends, out of which at least 5 must be relatives. You can invite in the following way: 5 out of 7 are related and 4 out of 8 are not related or 6 out of 7 are related and 3 out of 8 are not related or 7 out of 7 are related and 2 out of 8 are not related. =7C5× 8C4 +(7C6×8C3) +(7C7×8C2) =1470+392+28=1890.
11, 12, 20, 58, 234, 1168
630, 180, 60, 24, 12, 8, 5
1, 18, 44, 81, 131, 198
66, 220, 384, 543, 702, 861
Find the wrong number in the given number series.
119, 200, 300, 417, 565
In each of the following, one term is wrong. Find the WRONG term.
3, 5, 8, 14, 21, 34, 55
Find the wrong number in the given number series.
231, 241, 233, 239, 235, 243Find the wrong number in the given number series.
976, 720, 495, 297, 130, - 14Â
120, 140, 178, 232, 300, 360
126, 295, 520, 807, 1170, 1611
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