Find S20 of the series whose first terms are: 30, 22, 14, 6, ...
1 answer:
Answer:
- 920
Step-by-step explanation:
There is a common difference d between consecutive terms in the sequence, that is
d = 22- 30 = 14 - 22 = 6 - 14 = - 8
This indicates the sequence is arithmetic with sum to n terms given by
=
[ 2a₁ + (n - 1)d ]
where a₁ is the first term and d the common difference
Here a₁ = 30 and d = - 8 , thus
=
[ (2 × 30) + (19 × - 8) ]
= 10(60 - 152)
= 10 × - 92
= - 920
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Answer:
Step-by-step explanation:
If each day equal chance then p = Prob that a person is borne on a particular day = 1/365
Each person is independent of the other and there are two outcomes either borne in July or not
p = prob for one person not borne in July = (365-31)/365 = 334/365
a)Hence prob that no one from n people borne in July =
b) p = prob of any one borne in July or Aug = =0.1698
X- no of people borne in July or Aug
n =15
P(X>=2) =
=0.7505