The rate of earning money for both activities will be calculated by dividing the amount earned by the total time spent for each of the activity.
Babysitting: rate = ($30 / 5 hours ) = $6 / hour
Doing chores: rate = ($28 / 4 hours) = $7 / hour
Thus, Holly is able to earn money faster when doing the chores compared to when she do the babysitting if she work for the same amount of time for each.