If the four positive integers are selected randomly from the set of positive integers, then the probability that the number 1,3,7 and 9 are in the unit place in the product of 4 -digit, so selected is

Step-by-step solution

The number of digits on unit place of any number =10 n(S)=10 The necessary condition for becoming the digits 1,3,5 or 7 at the unit place of product of four numbers that the digits 1,3,5 or 7 at unit place of every number. array ll & n(A)=4 & P(A)= 4 10 = 2 5 array So, required y= ( 2 5 )⁴= 16 625