Sample space = { 15 odd + 15 even} =30 possible outcomes
In how many ways I can choose 3 tickets: ³⁰C₃
In how many ways I can choose 2 tickets with ODD number : ¹⁵C₂
In how many ways I can choose 1 ticket with EVEN number : ¹⁵C₁
The probability of getting 2 odds & 1 even (3 tickets are drawn) is
P( probability choosing 2 ODDS & 1 EVEN) = (¹⁵C₂ x ¹⁵C₁) / ³⁰C₃ = 45/116