Let the four numbers be x, x + 2, x + 4 and x + 6.=> x + x + 2 + x + 4 + x + 6 = 36=> 4x + 12 = 36 => x = 6The numbers are 6, 8, 10 and 12.Sum of their squares = 62 + 82 + 102 + 122 = 36 + 64 + 100 + 144 = 344.
A total of (7 + 3) persons = 10 personal can sit in 10! ways.If we consider three girls as one unit, total persons = 7 + = 8 (here all three girls sit together).No. of ways = 81 and the three girls can be arranged in 31 ways among themselves.So, the total number of ways when three girls sit together = 81 x 31When the girls don't sit together, number of ways = 101 - (81 x 31) = 81 (10 x 9 - 6) = 81 x 84 = 3386880
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