Question

What is the number of ways to arrange 5 objects from a set of 9 different objects?

Answer 1

for the first object, there are 9 possibilities
for the second object, there are 8 possibilities since we already used one
the pattern keeps going until we get to the fifth object

total number of possibilities = 9*8*7*6*5

Answer 2

A fish tank at a pet store has 10 goldfish. In how many different ways can Brian choose 3 goldfish to buy?

Answer 3

@Vocaloid

Answer 4

combination formula

nCr = n!(r!*(n-r)!) where n = 10 (number of total goldfish) and r = 3 (number of goldfish he wants)