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Digital clock question

Please refer to the attachment.
The answer is B.
Can someone please explain how to do this question. I am unsure where to begin.
What I've picked up: time difference of 41minutes, all digits should be different for two successive minutes.
But what numbers should I start with as this could take ages.
(edited 3 years ago)
Reply 1
Original post by As.1997
Please refer to the attachment.
The answer is B.
Can someone please explain how to do this question. I am unsure where to begin.
What I've picked up: time difference of 41minutes, all digits should be different.
But what numbers should I start with as this could take ages.


You cpuld write the two clocks as an 8 digit number. Fitst four are 1 clock.
Hours in digits 1,2,5,6
Minutes in 3,4,7,8
Hours: 5,6 are the same as 1,2 or +1. What can these values be
Minutes are: +41 or -19.
A bit of testing should get you there?
Reply 2
Original post by mqb2766
You cpuld write the two clocks as an 8 digit number. Fitst four are 1 clock.
Hours in digits 1,2,5,6
Minutes in 3,4,7,8
Hours: 5,6 are the same as 1,2 or +1. What can these values be
Minutes are: +41 or -19.
A bit of testing should get you there?

What I've understood from this is:
clock 1:
12:34
clock 2:
56:78
Is this what you meant?
Reply 3
Original post by As.1997
What I've understood from this is:
clock 1:
12:34
clock 2:
56:78
Is this what you meant?

abcdefgh
Clock 1: ab:ef
Clock 2: cd:gh
Then just work out the hours and minutes.
(edited 3 years ago)
First of all, how does the person asking the question know their neighbour has a digital clock in her living room? You don’t realise until looking back just how creepy some of those questions were
Reply 5
Original post by Greywolftwo
First of all, how does the person asking the question know their neighbour has a digital clock in her living room? You don’t realise until looking back just how creepy some of those questions were

Invited for tea?
Original post by As.1997
Invited for tea?


Maybe, maybe he was snooping around, these questions just need a backstory to them to clear things, also two digital clocks? One faster than the other at completely different times? Sounds like a crazy woman to me
(edited 3 years ago)
Reply 7
Original post by mqb2766
abcdefgh
Clock 1: ab:ef
Clock 2: cd:gh
Then just work out the hours and minutes.

For hours we have 0-24 i.e. 25 different possibilities. How do we narrow this down? I just read up an explanation and they said that the only possible combination for hours is 19 and 20. But, how did they even get to this conclusion?
Reply 8
Original post by As.1997
For hours we have 0-24 i.e. 25 different possibilities. How do we narrow this down? I just read up an explanation and they said that the only possible combination for hours is 19 and 20. But, how did they even get to this conclusion?

For a question like this you have to get your hands dirty. Just try some values and work out why thats the only +1 combimation with no repeats. Its similar for the minutes as well.
Reply 9
Original post by mqb2766
For a question like this you have to get your hands dirty. Just try some values and work out why thats the only +1 combimation with no repeats. Its similar for the minutes as well.

Thanks for your help, I got it :smile:
Reply 10
Original post by Greywolftwo
Maybe, maybe he was snooping around, these questions just need a backstory to them to clear things, also two digital clocks? One faster than the other at completely different times? Sounds like a crazy woman to me

:s-smilie:
Not realy. Its problem solving rather than applying a formula so you have to get stuck in. The hours reasoning should be quick and tbh, the minutes is fairly straightforward, the tens must be 3,5 and the digits 6,7,8.
Reply 12
Original post by mqb2766
Not realy. Its problem solving rather than applying a formula so you have to get stuck in. The hours reasoning should be quick and tbh, the minutes is fairly straightforward, the tens must be 3,5 and the digits 6,7,8.

Fair enough. Thank you!

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