1993 AMC 8 Problem 21
Attempt Problem 21 of the 1993 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1993 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
21.
If the length of a rectangle is increased by and its width is increased by then the area is increased by
Answer: D
Small hint:
New area (new length) (new width) times the old area
Big hint:
Multiply the two growth factors and to get the factor by which the area grows
Solution:
The new length is times the old and the new width is times the old, so the new area is times the old area.
That is an increase of
Thus, the correct answer is D .
Problem 21 in other years
- 1985 AMC 8
- 1986 AMC 8
- 1987 AMC 8
- 1988 AMC 8
- 1989 AMC 8
- 1990 AMC 8
- 1991 AMC 8
- 1992 AMC 8
- 1994 AMC 8
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