there are 8 railway stations along a rail line.in how many way can a train be stopped at 3 of these stations such that no two of them are consecutive?

Dear student,

The required number of ways=8P3

Use permutation

No.of ways to select 3 stations among 8 stations = 8C3No.of possibilities of 3stations might be consecutive = 6No.Of possibilities of 2 stations among those 3 might be consecutive = 30So, resultant answer is 8C3 - 6 - 30 = 20