At what time between 4 and 5 will the hands of a watch coincide?

I though the answer is 4:20 but the books answers 240/11 minutes past 4, could you please give an explanation. Appreciate your help.

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- February 17th 2013, 08:46 PMhisajeshClock problem...help.
At what time between 4 and 5 will the hands of a watch coincide?

I though the answer is 4:20 but the books answers 240/11 minutes past 4, could you please give an explanation. Appreciate your help. - February 17th 2013, 09:17 PMchiroRe: Clock problem...help.
Hey hisajesh.

Hint: The modulus (i.e. MOD 60) will be the same for both hands. In other words hand1 (MOD 60) = hand2 (MOD 60). You can decide whether you want the moduli to be continuous or not (I think the answer assumes non-discrete).