<span>3 black ribbons and 12 green ribbons
so P(</span><span>Lila selects a black ribbon)=3/(3+12)
=1/5
</span>2 black ribbons and 12 green ribbons left
P(<span>Jessica selects a green ribbon)=12/(12+2)
</span>=6/7
so P(<span>Lila selects a black ribbon and Jessica selects a green ribbon)
</span>=1/5*6/7
=6/35
ans is D
9 (c - 6) = 63
9c - 54 = 63
9c = 117
c = 13
5 buses.
32 + 32 + 32 +32 = 128. 4 buses will hold 32 people.
136-128 = 8. 1 bus will hold 8 peope
