Answer: There are 18 sets of five marbles including at least two red ones.
Step-by-step explanation:
Since we have given that
Number of red marbles = 3
Number of green marbles = 3
Number of lavender marbles = 1
total number of marbles = 3+3+1+1 = 8
We need to find the sets of five marbles including at least two red ones.
so, it becomes,
[tex]^3C_2\times ^4C_3+^3C_3\times ^4C_2\\\\=18[/tex]
hence, there are 18 sets of five marbles including at least two red ones.
