Copyright © University of Cambridge. All rights reserved.

## 'Inspector Morse' printed from http://nrich.maths.org/

This problem suited those of you who were very careful...
and some of you made errors along the way ...

Tom and Joseph from D.A.P.S. demonstrate the value of close collaboration:

"Our problem was to find out the units of time in the sentence that had to be decoded -
*Codes and hidden meanings*.
The way we solved this problem: we compared our notes and found an answer that we both agreed on. Joseph's method was: a space between letters is three units of
time, a space between words are seven units of time, a dah (a line-) is three units of time and a dot is one unit of time. First you add the units of time together to get the first number, then you add the three units of time for each space between letters, and at the end of each word you add seven units of time. Tom's method was to count all the spaces (there were 18 and there were 3 spaces between the words) so the next thing I did was to count the units of time in the letters. My answer was 166 units of time. Me and Joseph compared notes and we got the answer 166."

Jakob Plant, Ryan Campbell and Thomas Jewitt from Dauntsey's Aided Primary School set out their work very clearly:

c o d e s
-.-. --- -.. . ... = 38 Units (including 3 units between letters)
= 7 units (7 units between each word)
a n d
.- -. -.. = 19 units
= 7 units
h i d d e n
.... .. -.. -.. . -. = 36 units
= 7 units
m e a n i n g s
-- . .- -. .. -. --. ... = 52 units
= 166 units
KEY
- =3 units
. =1 units
gap between words = 7 units
gap between letters = 3 units

One of them added:
"First I worked out the message in
Morse code. I next worked out how
many units there were in each word.
Then I added up the units in the
gaps. Next I added up the totals
from each word and then I added the
units from between the words and I
got 166 units."

Well done to you all.