Which of following represents a physical change? a. the rusting of iron b. the tarnishing of the surface of copper in the presence of oxygen c. the electrolysis of water to produce hydrogen and oxygen d. the dissolution of sugar in water e. the decomposition of cinnabar (HgS) to mercury metal upon heating

compass can be used day and night, cloudy or sunny

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min