i think the first one is -3 and 7 but thats all i got
(1) This series consists of terms of an arithmetic sequence:
179 - 173 = 6
173 - 167 = 6
and so on, so that the <em>n</em>-th term in the series is (for <em>n</em> ≥ 1)
<em>a(n)</em> = 179 - 6 (<em>n</em> - 1) = 185 - 6<em>n</em>
Then the sum of the first 53 terms is
(2) This series has terms from a geometric sequence:
-12 / 6 = -2
24/(-12) = -2
-48/24 = -2
and so on. The <em>n</em>-th term is (again, for <em>n</em> ≥ 1)
<em>a(n)</em> = 6 (-2)ⁿ⁻¹
and the sum of the first 19 terms is
Multiply both sides by -2 :
Subtracting this from the first sum gives
and solving for the sum, you get
Answer:
The probability that Sandra will choose a red marble from the bag is 3 out of 11, or 3/11.
Step-by-step explanation: