By walking at 3/4th of his usual speed, a man reaches office 10 minutes later than usual. What is his usual time?  Select
A) 30min
B) 50min
C) 65min
D) 60min
E) 70min
let T be the usual time.   time spent=4T/3   therefore, 4T/3=T+10   4T=3T+30...therefor T=30min   30minNSWER:30min
<result>A</result>
By walking at 3/4th of his usual speed, a man reaches office 10 minutes later than usual. What is his usual time?