A man travelled a distance of 99 km in 9 hours. He travelled partly on foot @ 9 km/hr and partly on bicycle @ 18 km/hr. What is distance (in kms) travelled on foot?
The ratio of number of boys to the number of girls in a school of 432 pupils is 5 : 4. When some new boys and girls are admitted, the number of boys increase by 12 and the ratio of the boys to girls changes to 7 : 6. The number of new girls admitted is