How many signals can be made with 5 different flags by raising them any number at a time?
A 375
B 325
C 475
D 275
E 625
Permutations/Combinations
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In this case we need to find how many possibilities if 5 flags are used, then 4 flags, then 3 flags, then 2 flags and then 1 flag and add up the possibilities.
If 5 flags are used then the number of possibilities is 5*4*3*2* 1 or 120 possibilities.
If 4 flags are used then the number of possibilities is 5*4*3*2 or 120 possibilities.
If 3 flags are used then the number of possibilities is 5*4*3 or 60 possibilities.
If 2 flags are used then the number of possibilities is 5*4 or 20 possibilities.
If 1 flag is used then the number of possibilities is 5.
Then add up the possibilities 120 + 120 + 60 + 20 + 5 = 325 or choice B.
Take care,
Sionainn
If 5 flags are used then the number of possibilities is 5*4*3*2* 1 or 120 possibilities.
If 4 flags are used then the number of possibilities is 5*4*3*2 or 120 possibilities.
If 3 flags are used then the number of possibilities is 5*4*3 or 60 possibilities.
If 2 flags are used then the number of possibilities is 5*4 or 20 possibilities.
If 1 flag is used then the number of possibilities is 5.
Then add up the possibilities 120 + 120 + 60 + 20 + 5 = 325 or choice B.
Take care,
Sionainn
BA - Stanford University, MPP - Harvard University
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If we only raise 1 flag at a time, there are 5P1 ways to raise it.vaibhav101 wrote:How many signals can be made with 5 different flags by raising them any number at a time?
A 375
B 325
C 475
D 275
E 625
If we raise 2 flags at a time, there are 5P2 ways, to raise them.
Using the same logic, there are 5P3, 5P4 and 5P5, ways to raise 3, 4, and 5 flags at a time, respectively. Therefore, the total number of ways to raise any number of flags at a time is:
5P1 + 5P2 + 5P3 + 5P4 + 5P5 = 5 + 20 + 60 + 120 + 120 = 325
Answer: B
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