Inactive Tutor answered 02/01/16
Tutor
New to Wyzant
Batman and joker both travels in same direction
Batman's given speed is 60 mph
Joker's given speed 40 mph
Batman travels faster than joker by (60-40) 20 mph
Let's assume in x hours after starting Batman catches Joker
Hence in x hours Joker travels 40x miles and Batman travels 60x miles
when batman catches joker, Batman need to cover the initial distance of 60 miles between them, therefore: 60x=40x+60
=>60x-40x=60 ....... subtracting 40x from both sides
=>20x=60 ............... adjusting coefficients and operators
=>x=3 .................. dividing both sides by 20
Hence, Batman takes 3 hours to catch the Joker.