Question

# If there are 7 bands and 3 floats, in how many different ways can they be arranged?

Probability
total of 10 items they can be arranged in $$10!$$ ways but, 7 bands are identical, so there would be no change if they are arranged in any way, similarly with 3 floats.
Hence total number of ways $$= \frac{10!}{7!\times 3!} = 8\times9\times\frac{10 }{ 6} = 120$$ ways.