# The clock riddle

Found 5th Mar 2008
Supposing a clock takes 3 seconds to strike 3. How long will the same clock take to strike 7?

Groups

ten and half seconds

does 'strike' in this instance mean chime?

7 seconds ?

4 Hours and 3 seconds

Or does it only chime 3 times, no matter what time it is ?

14403 seconds

Predikuesi;1672560

ten and half seconds

This :thumbsup:

(1.5 seconds per strike)

9 seconds

surely if it was 1.5 strikes per second then 7 strikes would take

7/1.5 seconds

=

4.67 seconds

and 3 strikes would take 2 seconds...

I'm going to go with 10.5 seconds, no idea why it just sounds about right...:oops:

What? Explain this.

3 seconds to strike 3

3/3 = 1 strike per second

7 strikes = 7 seconds..........

gav989;1672752

surely if it was 1.5 strikes per second then 7 strikes would take 7/1.5 … surely if it was 1.5 strikes per second then 7 strikes would take 7/1.5 seconds=4.67 secondsand 3 strikes would take 2 seconds...

It would, which is why I typed 1.5 seconds per strike. I have no idea why it has shown up the other way round, but I suspect my computer hates me. It also keeps calling me Dave for some reason. :w00t:

(Thank you :oops:)

Original Poster

schaf;1672741

9 seconds

Correct. :thumbsup:

3 seconds, 3 strikes = 1.5 per interval

7 strikes = 6 intervals

So 6*1.5 = 9 seconds.

Those who said 10.5 seconds are doing a different version of the riddle (you googled maybe?) this is why I fiddled with the numbers! :roll:

Abvance;1672867

Those who said 10.5 seconds are doing a different version of the riddle … Those who said 10.5 seconds are doing a different version of the riddle (you googled maybe?) this is why I fiddled with the numbers! :roll:

Hey, I resent that!

I knew that the first strike started at 0, so it's 2 strikes in 3 seconds, or 1 strike every 1.5 seconds.

7 Strikes x 1.5 seconds = 10.5 seconds.

In my answer though, I forgot to take into account that the first strike still doesn't count, so like you say, it should have been 6 x 1.5 = 9

Abvance;1672867

Correct. :thumbsup:3 seconds, 3 strikes = 1.5 per interval7 strikes = 6 … Correct. :thumbsup:3 seconds, 3 strikes = 1.5 per interval7 strikes = 6 intervalsSo 6*1.5 = 9 seconds.Those who said 10.5 seconds are doing a different version of the riddle (you googled maybe?) this is why I fiddled with the numbers! :roll:

assuming that the strike takes zero time?

Abvance;1672867

Correct. :thumbsup:3 seconds, 3 strikes = 1.5 per interval7 strikes = 6 … Correct. :thumbsup:3 seconds, 3 strikes = 1.5 per interval7 strikes = 6 intervalsSo 6*1.5 = 9 seconds.Those who said 10.5 seconds are doing a different version of the riddle (you googled maybe?) this is why I fiddled with the numbers! :roll:

Write that out in a time line, it doesn't appear to add up.

I suspect my computer hates me. It also keeps calling me Dave for some … I suspect my computer hates me. It also keeps calling me Dave for some reason. :w00t:

I think that this Dave thing has gone too far - TV channel, n-s;what's next?

Alfonse;1672913

Write that out in a time line, it doesn't appear to add up.

Seconds - Strikes

0.0 - 1
1.5 - 2
3.0 - 3
4.5 - 4
6.0 - 5
7.5 - 6
9.0 - 7

yeah i agree it should be 9 seconds based on 6 intervals of 1.5 seconds

chesso;1672920

I think that this Dave thing has gone too far - TV channel, n-s;what's … I think that this Dave thing has gone too far - TV channel, n-s;what's next?

Prime Minister? :w00t:

nightswimmer;1673001

Prime Minister? :w00t:

ohhhhh! I never thought of that. What have I said?:w00t:

only 2 seconds out, boy I was sooooooooooo close:whistling:

Does it have any flashing lights

Cuz Im Deaf

But these answers all ignore the duration of the initial strike:

|Strike|Pause|Strike|Pause|Strike| = 3 seconds 3S+2P=3
|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike = n seconds 7S+6P=n

You cannot solve this without knowing either the duration of the strike or the duration of the pause. All you can say is that n=9-(2*strike duration) and n=7+(4/3*pause duration)

Eg If the strike time is 1s and there is no pause it will take 7 seconds
If the strike time is 0.8s and the pause time is 0.3s it would take 7.4 seconds
If the strike time is 0.2s and the pause time is 1.2s it would take 8.6 seconds

jah128;1674220

But these answers all ignore the duration of the initial … But these answers all ignore the duration of the initial strike:|Strike|Pause|Strike|Pause|Strike| = 3 seconds 3S+2P=3|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike|Pause|Strike = n seconds 7S+6P=nYou cannot solve this without knowing either the duration of the strike or the duration of the pause. All you can say is that n=9-(2*strike duration) and n=7+(4/3*pause duration)Eg If the strike time is 1s and there is no pause it will take 7 seconds If the strike time is 0.8s and the pause time is 0.3s it would take 7.4 seconds If the strike time is 0.2s and the pause time is 1.2s it would take 8.6 seconds

Yeah , you see that's what I was just writing :whistling: :-D :oops: (not)

chesso;1672911

assuming that the strike takes zero time?

As I said ^^^^^:;-)

Yep you did, sorry I missed it

I guess the point is the strike cannot take zero time, so the answer is definately less than 9 seconds, and the pause cannot take zero time, so the answer is definately longer than 7 seconds...

jah128;1674975

Yep you did, sorry I missed it :)I guess the point is the strike cannot … Yep you did, sorry I missed it :)I guess the point is the strike cannot take zero time, so the answer is definately less than 9 seconds, and the pause cannot take zero time, so the answer is definately longer than 7 seconds...

As you say:thumbsup: