@Synced23,
Difficulty level is 1.
There are C(43,10) ways to choose 10 of 43 numbers. There are C(5,5)*C(38,5) ways to choose the 5 correct numbers and 5 other numbers. Therefore, the probability of selecting all 5 correct numbers is C(38,5)/C(43,10) since C(5,5) is 1. The exact probability is 10*9*8*7*6/(43*42*41*40*39), which is approximately 0.00026.
C(m,n) is the number of combinations of m things taken n at a time.
C(m,n) = m!/[n! * (m-n)!]