The event E is picking 7 first regardless of the second pick. Furthermore, the very first condition is that 2 odd numbers are picked. So, we need the probability of picking 7 first and then an odd number as the second pick.
The only options that fulfill both conditions are: (7,3), (7,5), (7,7), (7,9).
The answer is then
[tex]E=\lbrace(7,3),(7,5),(7,7),(7,9)\rbrace[/tex]Where (a,b) represents picking a first and b second.
