A man was traveling on a motorcycle at the speed of 50 km/h for 2 1/2hours. Then a car full of youngster overtake him at a speed of 80 km/h. To overtake them he increased his speed to 70 km/h, but he could not overtake the car even after 2 1/2hours. How far did he travel in the total time of 4 hours?
The distances from A to B, B to C and C to D, are 12 kms. each. A man runs from A to B at a speed of X kms/hour. After reaching B, he rests for X hours and runs from B to C at double the previous speed. At C he rests for 2 X hours and runs from C to D at double his speed from B to C. He reaches D in 16 hrs after starting from A. Then a possible value of X is