plzz solve these Infosys problems

[sweet_madhu]

1>Trains leave from New York to Washington every hour on the
hour(1:00,2:00....).Trains leave from Washington to New York every
hour on the hour and half hour(1:00,1:30,2:0,2:30....).It takes a train 5
hrs to complete its journey from Washington to New York as well as
from new york to washington.A train leaves from new york to washington. Find out how many trains it will meet before it reaches washington.

2>In certain community, there are thousand married couples. Two thirds of the husbands who are taller than their wives are also heavier and three quarters of the husbands who are heavier than their wives are also taller. If there are 120 wives who are taller and heavier than their husbands, how many husbands are taller and heavier than their wives?

3>A cow was standing on a bridge, 5feet away from the middle of the bridge. suddenly a lightning express with 90 miles/hr was coming towards the bridge from nearest end of the cow.seeeing this the cow ran towards the express and managed to escape when the train is one feet away from the bridge. if it would have ran to opposite direction(ie away from train) it would have been hit the train one ft away from the end of the bridge. Calculate the length of bridge.

plzz tell me the approach to solve these questions.....