X and Y are parents of four married sons, one married daughter and one unmarried daughter living in a joint family. Two of the sons have two daughters and one son each. The other two have two sons and one daughter each. How many male members are there in the family.
A mini-van crosses two people walking at the speed of 4.8 kmph and 6 kmph in the same direction as that in which the mini-van is heading in 4.5 s and 9 s, respectively. What is the length of the mini-van?