Grouping Two Different Coloured Objects
Having three black objects B and one white object W they can be grouped in 7 ways like this:
| (BBBW) | (B,BBW) | (B,B,BW) | (B,B,B,W) | (B,BB,W) | (BBB,W) | (BB,BW) |
In how many ways can sixty black objects B and forty white objects W be thus grouped?