Four flags of different colours are given. How many different signals can be genrated, if a signal requires the use of two flags, one below the other?

Given 7 flags of different colours, how many different signals can be generated if a signal requires the use of two flags, one below the other?

Given 5 flags of different colours. How many different singnals can be generated if each signal requires the use of 2 flags, one below the other?

Given 7 flags of different colours,how many different signals can be generated if a signal requires the use of two flags,one below the other?

Given (i) 4 flags (ii) 5 flags of different colours, how many different Signals can be generated if each signal requires the use of two flags, one below the other ?

Given 4 flags of different colours, how many different signals can be generated, if a signal requires the use of 2 flags one below the other?

Given 4 flags of different colours, how many different signals can be generated, if a signal requires the use of 2 flags one below the other?

Given 4 flags of different colours, how many different signals can be generated, if a signal requires the use of 2 flags one below the other?