Answer
FarmerBooks.com
5,400
Work Step by Step
Set up a Venn diagram abbreviating set names to H, J F
and enter values into regions, in this order:
1000 into the intersection of all three$, H\cap J\cap F$.
1000 in the region $H\cap J$ but not $H\cap J\cap F, $to make a total of 2000,
500 in the region $H\cap F$ but not $H\cap J\cap F, $to make a total of 1500
100 in the region $J\cap F$ but not $H\cap J\cap F, $to make a total of 1$1$00
1000 in the region exclusive to H, to make a total of 3,500
600 in the region exclusive to J, to make a total of 3,600
1800 in the region exclusive to F, to make a total of 3,400
(see attached image)
Reading the the diagram:
$n(H\cup J)=3,500+600+100=4,200,$
$n(H\cup F)=3,500+1800+100= 5,400$
Merger with FarmerBooks.com gives a combined customer base of 5,400
