Answer:
343
Explanation:
Finding? How many people with a library card should he expect in the population?
Important? Population = 700. Sample 1= 53%. Sample 2 = 51%. Sample 3 = 43%.
How? Average the 3 samples percentages together. The percent sign tells us what the sample size is (% = out of 100). Set up the proportions for library card to sample size and then library card to population. Cross multiply.