NDA Math Probability Part 2

Prime number between 1 to 10 are 2,3,5,7 .
Now, number of ways of selecting 2 prime number out of 4 prime number =‌4C2=6.
Number of ways of selecting 2 numbers out of 10 numbers =‌10C2=45
∴ Required probability =

6

45

=

2

15