The sum of three numbers is 67. If the ratio of the first number to the second number is 3 : 5 and that of the second number to the third number is 4 : 7, then what is the second number ?
A man travelled a distance of 50 km in 8 hours. He travelled partly on foot at 5 km/hr and partly on bicycle at 7 km/hr. What is the distance (in kms) travelled on foot?