They both seem to be substitution
Respuesta:
54 discos son de música clásica
9 discos son de música para bailar
:)
Answer:
(3, -2)
Step-by-step explanation:
Find the midpoint coordinates (x, y) of points A(2, - 5) and B(4, 1)
x-coordinate of the midpoint is (2+4)/2 = 6/2= 3
y-coordinate of the midpoint is (-5+1)/2 = -4/2= -2
The mid point coordinates are (3, -2)
18 choose 7
=C(18,7)
=18!/(7!(18-7)!)
=31824
OR
18 choices for first passenger,
17 choices for second passenger,
....
12 choices for 7th passenger,
so total = 18*17*16...12
but there are 7! ways to order the 7 passengers, so
number of groups
=18*17*16...12/7!
=31824 as well