A man is traveling at 3∕5 th of his usual speed and is late by 20 minutes. Formula used: Time = Distance ÷ Speed Let the usual time taken by the man be T minutes. When traveling at 3/5th of the usual speed, time taken =T×(5∕3). Difference in time: T×(5∕3)−T=20 minutes. Calculation: ⇒T×(5∕3)−T=20 ⇒(5T∕3)−T=20 ⇒(5T−3T)∕3=20 ⇒2T∕3=20 ⇒T=20×(3∕2) ⇒T=30 minutes
