Question

In a store, a sample of 60 pens was selected from a box of 1,200 pens. Of these 60, 4 pens did not work. About how many pens could be expected to not work in the group of 1,200 pens?

Answer 1

Ok so if 1200 total pens and 60 were taken that's a ratio of 1200/60=20

out of 60pens 4 didn't work, again ratio is 4/60=1/15 so about 1/15 of the pens didn't work. 

so we have 1200pens * 1/15broken ratio = 80 pens or we can say 

20*4=80pens won't work from 20 groups of 60 and 4 out of 60 not working is 20*4=80 not working from total batch of 1200.

hope this helps you some! thank you!!!!!!!!!