A 4-column table with 3 rows. Column 1 has entries run, do not run, total. Column 2 is labeled lift weights with entries 40, blank, 65. Column 3 is labeled do not lift weights with entries blank, x, blank. Column 4 is labeled total with entries 75, blank, 120. Can you determine what number x represents from the information given? Explain how you got your answer.