A thief runs at a constant speed of 60 metres per minute. After one minute, a police officer chases down the robber to catch him. He starts at a speed of 60\(m/minute\), and gradually increases his speed by 10\(m/minute\) every minute after that. Determine the time required for the cop to catch the thief.
 
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The Policeman takes  minutes to catch the thief.