math
posted by Bryan on .
Almost everyone at the Bright Corporation reads a daily newspaper on a regular basis. In fact, altogether te company employs 2,940 people,of whom70% read The Daily News,45% read The Courier and 60% read The inquirer.
One fourth of the employees reads The Daily News and The Courier, and 30% read The Inquirer and The Courier, and 35% read The Daily News and The Inquirer. One tenth of the people read all three newspapers on a regular basis.
a. how many people read only The Daily news?
b. How many people read only The Courier?
c. How many people read on The Inquirer?
d. How many people don't read any newspaper?

Draw your 3circle Venn diagram. Label the circles D,C,I
DCI = .1
so
DC only = .15 (.25.10)
CI only = .20 (.30.10)
DI only = .25 (.35.10)
D only = .20 (.70  .15  .10  .25)
C only = .00 (.45  .15  .10  .20)
I only = .05 (.60  .25  .10  .20)
Add up all the percentages and it is clear that only 90% of the employees read any papers.
That makes .9*2940 = 2646 readers.
So,
a. D only = .2*2940 = 588
b. C only = 0
c. I only = .05*2940 = 147
d. None = .10*2940 = 294 
95% of the employees read any newspaper, therefore 5% don't read and newspaper. D should be 147