Test statistic in a two-sample z test for the difference of proportions

Market researchers wondered if teens were more or less likely than adults to use their mobile phone as an alarm clock. The researchers surveyed a random sample of people and removed those who didn't have a mobile phone. Here are the results:

The researchers want to test if these results suggest a significant difference between the proportions of teens and adults that use their phone as an alarm clock. Assume that all conditions have been met.