Question

if a number of two digits formed from 2 3 5 7 9 witout repition

Answer 1

Number of digits = 5
To form = 2 digits
Therefore, it is equal to 5C2
= (5 x 4 x 3 x 2 x 1) / (2 x 1)
= 5 x 4 x 3
= 60