Answer:
125/286
Explanation:
First we calculate the numerator of the desired probability:
"N(___)" means "The number of ways we can choose___)
N[ (3 girls AND 7 boys) OR (4 girls AND 6 boys) ]
The word "AND" suggests MULTIPLICATION, the word "OR" suggests ADDITION:
N(3 girls)*N(7 boys) + N(4 girls)*N(6 boys)
C(6,3)*C(7,7) + C(6,4)*C(7,6) = 20*1 + 15*7 = 125