Number of ways of selecting 6 shoes,out of 8 pairs of shoes,having exactly two pairs is

There are 12 pairs of shoes in a box. Then the possible number of ways of picking 7 shoes so that there are exactly two pairs of shoes are

There are 8 different pairs of socks.The number ways of selecting total 6 socks such that exactly 2 pairs are taken is

Find the number of ways of selecting 3 pairs from 8 distinct objects.

The number of 6 digit numbers that can be made with the digits 1,2,3 and 4 and having exactly two pairs of digits,is

There are four pairs of shoes of different sizes. Each of the 8 shoes can be coloured with one of the four colours. Black, Brown, White and Red. The number of ways the shoes can be coloured so that in atleast three pairs, the left shoe and the right shoe do not have the same colour is

Your pair of shoes has a mass of 780 g. If each shoe has exactly the same mass, what is the weight of each shoe?