In a lottery, ydu must pick five numbers from 30. How many different ways of doing this are there?

a)810000

b)243000000

c)142506

d)17100720

I have 8 books and need to choose 3 to take on holiday. How many different groups of three could I take?

a)336

b)70

c)6720

d)56

A password must be created using 5 different digits (from 0 to 9). How may different passwords are there?

a)30240

b)15120

c)3024

d)252

Mr. Boom chooses three students from a class of 20 to help him clean the windows. In how many ways could he work this

a)1140

b)3420

c)6840

d)8000