Question

one forth of the villains nabbed by the Second-Rate Superheroes were jaywalkers. One-ninth of those were illegal double parkers. What fraction of the villains were both jay walkers and illegal double parkers.

Answer 1

1/36

Explanation:

You want the fraction of villains that are both jay walkers and double-parkers, given that 1/9 of jay walkers are double-parkers and 1/4 of villains are jay walkers.

Doubly-bad villains

The fraction of villains that both jay walk and double park is 1/9 of 1/4 of all villains.

1/9 × 1/4 = 1/(9×4) = 1/36

1/36 of all villains are both jay walkers and double parkers.