Answer:
1716 ;
700 ;
1715 ;
658 ;
1254 ;
792
Step-by-step explanation:
Given that :
Number of members (n) = 13
a. How many ways can a group of seven be chosen to work on a project?
13C7:
Recall :
nCr = n! ÷ (n-r)! r!
13C7 = 13! ÷ (13 - 7)!7!
= 13! ÷ 6! 7!
(13*12*11*10*9*8*7!) ÷ 7! (6*5*4*3*2*1)
1235520 / 720
= 1716
b. Suppose seven team members are women and six are men.
Men = 6 ; women = 7
(i) How many groups of seven can be chosen that contain four women and three men?
(7C4) * (6C3)
Using calculator :
7C4 = 35
6C3 = 20
(35 * 20) = 700
(ii) How many groups of seven can be chosen that contain at least one man?
13C7 - 7C7
7C7 = only women
13C7 = 1716
7C7 = 1
1716 - 1 = 1715
(iii) How many groups of seven can be chosen that contain at most three women?
(6C4 * 7C3) + (6C5 * 7C2) + (6C6 * 7C1)
Using calculator :
(15 * 35) + (6 * 21) + (1 * 7)
525 + 126 + 7
= 658
c. Suppose two team members refuse to work together on projects. How many groups of seven can be chosen to work on a project?
(First in second out) + (second in first out) + (both out)
13 - 2 = 11
11C6 + 11C6 + 11C7
Using calculator :
462 + 462 + 330
= 1254
d. Suppose two team members insist on either working together or not at all on projects. How many groups of seven can be chosen to work on a project?
Number of ways with both in the group = 11C5
Number of ways with both out of the group = 11C7
11C5 + 11C7
462 + 330
= 792
Answer:
A.
Step-by-step explanation:
Answer:
Part A:
(1) x + y = 95
(2) x = y + 25
Part B:
The number of minutes Eric spends playing volleyball each day is 35 minutes
Part C:
It is not possible for Eric to have spent exactly 35 minutes playing basketball
Step-by-step explanation:
The total time Eric plays basketball and volleyball = 95 minutes
The time duration Eric plays basket ball = x
The time duration Eric plays volleyball = y
Part A:
The pair of relationships between the number of minutes Eric plays basketball (x) and the number of minutes he plays volleyball (y) are;
(1) x + y = 95
(2) x = y + 25
Part B:
By substituting the value of x in equation (2) into equation (1), we have;
x + y = (y + 25) + y = 95
2·y + 25 = 95
2·y = 95 - 25 = 70
y = 70/2 = 35 minutes
Therefore, Eric spends 35 minutes playing volleyball every day
Part C:
It is not possible for Eric to have spent only 35 minutes playing basketball because, given that he plays basketball for 25 minutes longer than he plays volley, the number of minutes he spends playing volleyball will then be given as follows;
x = y + 25
35 = y + 25
y = 35 - 25 = 10 minutes
The total time = x + y = 10 + 35 = 45 minutes ≠ 95 minutes.
Answer:
Radius, r, is 3.75
Step-by-step explanation:
From the given diagram,
AB = 9
AC = 6 + r
BC = r
Thus applying the Pythagoras theorem, we have;
= 
+ 
= 
+ 
36 + 12r + = 81 +
collecting like terms,
12r = 81 - 36
12r = 45
r = 
= 3.75
r = 3.75
The radius is 3.75.
I believe the answer is 36= -10.4!
Sorry if I'm wrong though.
