Answer:
r=
Step-by-step explanation:
The sum to infinity of a geometric series is calculated as
S∞ = ; | r | < 1
where a₁ is the first term and r the common ratio
here a₁ = 15 and S∞ = 45 , then
45 = ( multiply both sides by (1 - r ) )
45(1 - r) = 15 ( divide both sides by 45 )
1 - r = =
( subtract 1 from both sides )
- r = - 1 = -
( multiply both sides by - 1 )
r =
Answer:
(a) 896
(b) 1000
(c) 910
Step-by-step explanation:
Number of women = 8
Number of men = 6
A committee consisting of 3 men and 3 women is to be formed.
(a) 2 of the men refuse to serve together.
Number of men who don't want to serve together = 2
Remaining men = 4
Total ways = Both men who don't want to serve together are not selected + only one of them is selected.
(b) 2 of the women refuse to serve together.
Number of women who don't want to serve together = 2
Remaining men = 6
Total ways = Both women who don't want to serve together are not selected + only one of them is selected.
(c)1 man and 1 woman refuse to serve together.
Ways = Total ways - Both man and woman are select who refuse the serve together