A man intends to complete a journey of 24 km in 8 hours. If he travels at a speed of 4km/hr for the first four hours, at what speed does he need to travel for the remainder of the journey to be right on time?
He covers 4km/hr*4hrs = 
<gadget id="calculator">4*4</gadget>
<output>16</output>
16km in the first 4 hours.
He has 24-16 = 
<gadget id="calculator">24-16</gadget>
<output>8</output>
8km left to cover.
He has 8-4 = 
<gadget id="calculator">8-4</gadget>
<output>4</output>
4 hours to cover the remaining 8km.
He has to travel at a speed of 8km/4hrs = 2km/hr to be right on time.

<result>2</result>