Geometry Word Problem

Question

From 15,000 graphing calculators produced by a​ manufacturer, an inspector selects a random sample of 450 calculators and finds 4 defective calculators. Estimate the total number of defective calculators out of the 15,000.

Answer 1

Here we can set up a proportion: 4 is to 450 as x is to 15000:

4 x

--- = ------

450 15000

To solve we cross-multiply: 450x = 15000*4

450x = 60000

x = 133.33

can't have 1/3 of a calculator, so round off to 133

Answer 2

4/450 = x/15000 using ratios,

x = 133.3 will be defective