Among the Natural no.s {1,2,3,.....23,24,25},in how many ways we can draw 11 no.s so that no two of them are consecutive?

Dear Borah, 

first let there be a gap of one number between every two consecutive selections. when this is done, we have fixed 11*2 -1 =21 consecutive numbers. each of the remaining 4 numbers can be inserted into any one of 12 spaces. thus the number of ways=12*12*12*12=12⁴

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