Difference between revisions of "1953 AHSME Problems/Problem 11"
Line 1: | Line 1: | ||
− | A running track is the ring formed by two concentric circles. It is <math> 10</math> feet wide. The circumference of the two circles differ by about | + | A running track is the ring formed by two concentric circles. It is <math>10</math> feet wide. The circumference of the two circles differ by about: |
+ | <math>\textbf{(A)}\ 10\text{ feet} \qquad | ||
+ | \textbf{(B)}\ 30\text{ feet} \qquad | ||
+ | \textbf{(C)}\ 60\text{ feet} \qquad | ||
+ | \textbf{(D)}\ 100\text{ feet}\ \textbf{(E)}\ \text{none of these} </math> | ||
== Solution == | == Solution == |
Revision as of 11:19, 22 April 2020
A running track is the ring formed by two concentric circles. It is feet wide. The circumference of the two circles differ by about:
Solution
Call the radius of the outer circle and that of the inner circle . The width of the track is . The circumference of a circle is times the radius, so the difference in circumferences is feet. If we divide each side by , we get feet.
See Also
1953 AHSC (Problems • Answer Key • Resources) | ||
Preceded by Problem 10 |
Followed by Problem 12 | |
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 • 31 • 32 • 33 • 34 • 35 • 36 • 37 • 38 • 39 • 40 • 41 • 42 • 43 • 44 • 45 • 46 • 47 • 48 • 49 • 50 | ||
All AHSME Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.