A 7 digit number is such that the digits at both the extremes are 1 and the rest of the digits are 0 except the middle digit. Also it is known that the number is divisible by 13. What is the middle digit of the number?
A dog, which is sitting inside a tunnel XY, at a distance of 50 m from the end X, notices a train approaching the end X of the tunnel from the outside. Now, if the dog runs towards the end X, then the train would meet it exactly at X. if the dog runs towards the end Y instead, then the train would meet it exactly at Y. which of the following is not a possible value of the length XY ( in m) of the tunnel ?