Question of the day 12-2-2017

A man driving his bike at 24 kmph reaches his office 5 minutes late. Had he driven 25$\mathrm{ <span\; style="background:\; white;\; font-family:\; "Times\; New\; Roman",\; serif;\; font-size:\; 16pt;">faster\; on\; an\; average\; he\; would\; have\; reached\; 4\; minutes\; earlier\; than\; the\; scheduled\; time.\; How\; far\; is\; his\; office?</span><span\; style="font-family:\; Helvetica,\; sans-serif;\; font-size:\; 8.5pt;"><br\; style="box-sizing:\; border-box;">\; <span\; style="-webkit-text-stroke-width:\; 0px;\; box-sizing:\; border-box;\; font-variant-caps:\; normal;\; font-variant-ligatures:\; normal;\; orphans:\; 2;\; widows:\; 2;\; word-spacing:\; 0px;"><br\; style="box-sizing:\; border-box;">\; <br>\; </span><span\; style="font-family:\; "Times\; New\; Roman","serif";\; font-size:\; 16.0pt;">a)\; 18\; km</span><span\; style="font-family:\; "Times\; New\; Roman",\; serif;\; font-size:\; 16pt;"><o:p></o:p></span></span>}$

b) 24 km

c) 30 km

d) 36 km

$\mathrm{<span\; style="font-family:\; Helvetica,\; sans-serif;\; font-size:\; 8.5pt;"><span\; style="color:\; blue;">\; </span></span>}$

e) None.