from a total of 3 boys and 4 girls , how many 4 - person committees can be selected if the committee must have exactly 2 boys and 2 girls ?
"answer = c = 18 no of 4 person committees that can be formed = 3 c 2 * 4 c 2 = 18 answer a"
multiply(multiply(const_3, 3), multiply(3, 2))