In a sample of 1500 new iPhones 12 were found to be defectiv

In a sample of 1500 new iPhones, 12 were found to be defective. At this rate, how many defective iPhones would be expected in a sample of 100,000 new iPhones? Use a proportion to set up and solve this problem.

Solution

In a sample of 1500 new iPhones, 12 were found to be defective. Thus, the proportion of defective iphones to the total number of iphones, in the sample of  1500 new iPhones is 12: 1500 = 1:125. Therefore, it can be expected that in a vsample of 100,000 new iPhones, the number of 100,000 new iPhones is (1/125)*100000 = 800.