The Grammar club has 20 members: 10 boys and 10 girls. A 4-person committee is chosen at random. What is the probability that the committee has at least 1 boy and at least 2 girls?

The four-person subcommitte could have:

2 boys and 2 girls: _{10}C_{2} x _{10}C_{2}

1 boy and 3 girls: _{10}C_{1} x _{10}C_{3}

Find each of the two products and add them togehter.