Answer:
55
Step-by-step explanation:
Combinations formula is used to make choice of 'R' out of 'N' options =
N(C)R = N ! / [ R ! . (N-R)! ]
Total choices to choose 4 out of 8 friends = 8C4
= 8! / (4! 4!)
= 70
Choices for calling them 2 together = 2C2 x 6C2
= 1 x [ 6! / (2! 4!)]
= 15
So : Number of choices that the 2 friends are not called together = Total choices - choices they are called together
= 70 - 15 = 55
Answer:
90º
Step-by-step explanation:
A triangle = 180º.
m<Z = 90º
So m<x + m<y = 180 - 90
That equals 90º
<em>Hope that helps!</em>
Answer:
D.
Step-by-step explanation:
The length of the unmarked side of the triangle is found by using Pythagoras:
x sqrt (10^2 - 6^2)
= sqrt 64
= 8.
The length of the curved part = 1/2 * pi * 10 = 5pi
Perimeter = 8 + 6 + 5pi
= 14 + 5pi
