EXAMPLE
3.3.14
The editorial
board of the National Requirer has decided to launch two new series of investigative
reports. One series will involve the theme
"Elvis
____ my ____!"
For this series,
the writers will generate a story line by filling in the first blank with an
item from this list:
"loved"; "sang to"; "got sick on"; "smoked" and filling in the second blank
with an item from this list:
"fig
tree"; "living
room carpet";
"cat".
The other series
will involve the theme "Aliens ____ my ____!"
The writers will
generate a story line by filling in the first blank with an item from this
list: "attacked";
"rescued";
"probed";
and filling in
the second blank with an item from this list:
"home
town"; "trailer
park"; "granny's
arrest record"
How many story
lines are possible?
SOLUTION
A story line is
either an ÒElvisÓ story line or an ÒaliensÓ story line. To generate an ÒElvisÓ headline we need
to make two independent decisions:
1. Fill in the first blank. 4
options
2. Fill in the second blank. 3 options
(4) times (3) =
12 possible ÒElvisÓ headlines (story lines).
To generate an ÒaliensÓ
headline we need to make two independent decisions:
1. Fill in the first blank. 3
options
2. Fill in the second blank. 3 options
(3) times (3) =
9 possible ÒaliensÓ headlines (story lines).
The total number
of possible headlines is 9 + 12 = 21