To find the percentages that they ask us, we must first know 100%, that is, the number of people surveyed:
250 as the statement says.
what percentage of the people exercise regularly?
People who exercise regularly are 5 + 55 = 60
If 250 is 100%, then 60 must be 24%.
24% of the people exercise regularly.
What percentage of the people smoke?
People who smokes are 5 +45 = 50.
If 250 is 100%, then 50% must be 20%.
20% of the surveyed people smoke.