Upon examining the contents of 38 backpacks, it was found that 23 contained a black pen, 27 contained a blue pen, and 21 contained a pencil, 15 contained both a black pen and a blue pen, 12 contained both a black pen and a pencil, 18 contained both a blue pen and a pencil, and 10 contained all three items. how many backpacks contained none of the three writing instruments?

2

Explanation:

Given

Total bags=38

No of bags containing black pen is

No of bags containing blue pen

No of bags containing  pencil

no of bags containing both Black pen & blue

no of bags containing both Black pen & Pencil

no of bags containing both Blue pen & Pencil

no of bags containing all

using Venn diagram

and we know

Therefore there are 2 bags which are empty.

the act of deciding on matters of the economy. economic decision making is routinely conducted by finance ministers, economic advisors, heads of major central banks and business leaders and can have profound effects on a major economy.

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;