How much time will Bus A take to cross Bus B (from the moment they meet) running in opposite directions (towards each other)? I: The respective ratio of speeds of Bus A and Bus B is 9 : 5. The sum of the lengths of Bus A and Bus B is 1400 metre. II: Bus A can cross a signal pole in 15 seconds. It can cross 750 metre long stand in 20 seconds.

From statement I: Relative speed = 9x + 5x = 14x units Sum of Length of buses = 1400 metre Required time = 1400/(14 x) = no result From statement II: Let length of bus A = y Speed of Bus A = y/15 = (y + 750 )/20 ⇒ 20 y = 15 y + 11250 ⇒ 5 y = 11250 ⇒ y = 2,250 = length of bus A Now we can’t find answer by only one statement & if we use both, it will contradict each other because in 1st statement, sum of length of two buses is 1400 & in 2nd statement, length of bus A only is 2250 So we cant find answer by even using both statements.