Combinatorics Problem by me

Probability Level 3

A telegraph has 5 arms and each arm is capable of 4 distinct positions, including the position of rest. Find the total number of signals that can be made.


The answer is 1023.

Abhiram Rao by Abhiram Rao , 18, India

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1 solution

Ashish Menon
May 14, 2016

Each arm is capable of 4 positions. So , first arm is capable of 4 positions, second too of 4 positions, third too of 4 positions, fourth too of 4 positions , fifth too of 4 positions. So, the number of positions it can make = 4 × 4 × 4 × 4 × 4 = 4 5 = 1024 4×4×4×4×4 = 4^5 = 1024 But the telegraph wont send a signal in rest position, so the number of wignals it can make = 1024 − 1 = 1023 1024 - 1 = \boxed{1023} .

2 Helpful 0 Interesting 0 Brilliant 0 Confused

Yes. Did the exact same

Aditya Kumar - 5 years ago

You could have elaborated on the ending for those of us not familiar with a telegraph.

ATVthe King - 10 months, 3 weeks ago

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