Answer:
Odds to be given for an event that either Romance or Downhill wins is 11:4
Step-by-step explanation:
Given an odd, r = a : b. The probability of the odd, r can be determined by;
 Pr(r) = 
 ÷ ( 
So that;
Odd that Romance will win = 2:3
Pr(R) = 
 ÷ ( 
 = 
 ÷ 

 = 

Odd that Downhill will win = 1:2
Pr(D) = 
 ÷ (
 = 
 ÷ 

 = 

The probability that either Romance or Downhill will win is;
Pr(R) + Pr(D) = 
 + 

 = 

The probability that neither Romance nor Downhill will win is;
Pr(neither R nor D) = (1 - 
)
 = 

The odds to be given for an event that either Romance or Downhill wins can be determined by;
 = Pr(Pr(R) + Pr(D)) ÷ Pr(neither R nor D)
 = 
 ÷ 

 = 

Therefore, odds to be given for an event that either Romance or Downhill wins is 11:4