In: Statistics and Probability
If a license plate has four different digits on it, what is the probability that the numbers on the plate will not be in either consecutive increasing or consecutive decreasing order? Show you work.
Solution:
total number of numbers = 10
number of different license plates formed by four different numbers = 10C4 = 5040
number of plates will be in either consecutive increasing or consecutive decreasing order = 14
they are :
(0,1,2,3),(1,2,3,4),(2,3,4,5),(3,4,5,6),(4,5,6,7),(5,6,7,8),(6,7,8,9),(9,8,7,6),(8,7,6,5),(7,6,5,4),(6,5,4,3),(5,4,3,2)(4,3,2,1),(3,2,1,0)
number of plates will not be in either consecutive increasing or consecutive decreasing order = 5040 - 14 = 5026
probability that the numbers on the plate will not be in either consecutive increasing or consecutive decreasing order = 5026 / 5040 = 0.9972