Work Step by Step
The interval 30-39 has no frequency but you have to put it as part of the table with the frequency of 0. Despite that the problem has a gap, it still needs to be part of the table.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.