The chance of an event happening is the square of the chance of a second event but the odds against the first are the cubes of the odds against the second. The chances of happening of each event are

Let the chance of the second event be ‘P’. Then the chance of the first event is

odds against the first event are as

and odds against the second event are

Hence , according to the given in the question.

We have

Or

and

Hence the probability of the first event