A person takes 20 minutes more to cover a certain distance by decreasing his speed by 20%. What is the time taken to cover the distance at his original speed?	Pick one.
A) 1 hour 70 minutes B) 1 hour 28 minutes C) 1 hour 20 minutes D) 2 hour 20 minutes E) 1 hour 30 minutes
Let the distance and original speed be d km and k kmph respectively.   d/0.8k - d/k = 20/60 =&gt; 5d/4k - d/k = 1/3   =&gt; (5d - 4d)/4k = 1/3 =&gt; d = 4/3 k   Time taken to cover the distance at original speed   = d/k = 4/3 hours = 1 hour 20 minutes.   Answer: 1 hour 20 minutes
<result>C</result>
A person takes 20 minutes more to cover a certain distance by decreasing his speed by 20%. What is the time taken to cover the distance at his original speed?