A slow clock loses 25 minutes a day. At noon on the first of October, it is set to show the correct time. When will this clock next show the correct time?

Vicky.

Could I get some help pls.

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- Aug 19th 2009, 06:54 PMVicky1997clock problem
A slow clock loses 25 minutes a day. At noon on the first of October, it is set to show the correct time. When will this clock next show the correct time?

Vicky.

Could I get some help pls. - Aug 19th 2009, 08:10 PMGamma
does am/pm count?

Like will it "show the correct time" after it loses 12 hours or does it need to lose a full 24 hours? - Aug 19th 2009, 09:11 PMVicky1997
I am not sure. But i don't think the problem mentioned anything about it. And could you pls explain why it makes a difference?

Vicky. - Aug 19th 2009, 10:05 PMeXist
It makes a difference because on a clock with only 12 hours (no pm or am) it will be shorter since there are less hours to rotate through. With a 24 hour clock (am and pm included) there will be more hours to rotate through.

- Aug 19th 2009, 10:40 PMGrandad
Hello VickyI'll assume that it's a 12-hour clock - so it shows the 'correct' time if, for example, it's actually 8 pm but the clock 'thinks' it's 8 am.

In one day ( minutes) it loses minutes. So it is running at of the correct speed.

So minutes after noon on the first of October, the clock 'thinks' that minutes have elapsed. The clock will first show the correct time, then, when the difference between these two numbers of minutes , because the clock will then be exactly hours slow. (If it's a hour clock, you'll have to make this hours, or minutes.) So:

We now need to find the date and time, minutes after noon on 1st October.

minutes days

and 0.8 days = 19.2 hours = 19 hours 12 minutes

So it's 19 hours 12 minutes after noon on 29th October, or 7:12 am on 30th October.

Grandad

PS Here's a much more obvious way of doing the calculation.

It takes one day for the clock to lose 25 minutes. So in days it loses 720 minutes. Sorry I made it seem a lot harder than it really was!