Question

Twenty sharpened pencils are placed in a box containing an unknown number of unsharpened pencils. suppose 15 pencils are removed at random and five of the removed pencils are sharpened. based on this, is it reasonable to assume that the number of unsharpened pencils was 40?

Answer 1

assuming that the 15 samples has a normal distribution. then the fraction of the sharpened pencil = 5 / 15 = 1 / 3

then solve the total number of pencil in the box
total pencil = (20) / ( 1 / 3)
total pencil = 20*3
total pencil = 60

so the number of unsharpened pencil = 60 - 20 = 40 pencils