Hard Question

Buses from town A to town B leave every hour on the hour(for example:6:00,7:00,...)

Buses from town B to town A leave every hour on the half hour(for example:6:30,7:30,...)

The trip between town A and town B takes 5 hours.Assume the buses travel on the same road.

If you get on a bus from town A,how many buses from town B do you pass on the road(not including those at the stations)?

Medium Question

A record shows that a school have 81 people kick football,74 people play basketball and 44 people play badminton.There are also 59 people who play both basketball and football,37 people who play football and badminton,27 people who play basketball and badminton.There are also 21 people who play the three games.

Find the total number of people

Easy Question

Find the value of 1^2-2^2+3^2-4^2+5^2-6^2......-100^2
*1^2=1 , 2^2=4 3^2=9 , 4^2=16

Hard Question

a+b+c =0 , simplify (a+b)(b+c)(c+a)+abc

Medium Question

1/a + 1/b + 1/c = 1/2009
find the value of a,b,and c

Easy Question

a,b,and c are positive integers and a < b < c.
m is an integer,where 1/a + 1/b + 1/c =m
find the value of a,b,and c