Answer:
The number of cyclists on week 4 is 53.
Step-by-step explanation:
The mean is calculated by dividing the sum of numbers by how many number there are. In this case we have 4 weeks. The mean is 43, meaning in total, Rita had recorded
[tex]43 \times 4 = 172[/tex]
172 cyclists.
Now we can subtract the number of cyclists recorded on every other week, leaving the answer to the question.
[tex]172 - 42 - 39 - 38 = 53[/tex]
Rita recorded 53 cyclists on week 4.