1970 AHSME Problems/Problem 19

Revision as of 13:43, 2 October 2014 by Timneh (talk | contribs) (Created page with "== Problem == The sum of an infinite geometric series with common ratio <math>r</math> such that <math>|r|<1</math> is <math>15</math>, and the sum of the squares of the terms o...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Problem

The sum of an infinite geometric series with common ratio $r$ such that $|r|<1$ is $15$, and the sum of the squares of the terms of this series is $45$. The first term of the series is

$\text{(A) } 12\quad \text{(B) } 10\quad \text{(C) } 5\quad \text{(D) } 3\quad \text{(E) 2}$

Solution

$\fbox{C}$

See also

1970 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 18
Followed by
Problem 22
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png