Solution:
The numbers of ways of selecting 3 number our of 30 is . But this include 28 ways of selecting 3 consecutive numbers. [viz (1, 2, 3), (2, 3, 4), 3, 4, 5),……,(28, 29, 30)]
Thus, required number of ways is .
The number of ways selecting three numbers from 1 to 30, so as to exclude every selection of three consecutive number is:
The number of ways selecting three numbers from 1 to 30, so as to exclude every selection of three consecutive number is:
