You can 
put this solution on YOUR website! If the probability of an event is 0.7, what are the odds in favor of the event?
Write the decimal 0.7 as a fraction 
.  It doesn't reduce.
probability = 0.7 = 
, which means 7 successes out of 10 trials, 
which means 7 successes to 10-7 = 3 failures
Odds in favor means successes : failures, so that's 
7 successes to 3 failures or  7:3
Edwin