1990 AMC 8 Problem 2

Attempt Problem 2 of the 1990 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 1990 AMC 8 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

2.

Which digit of 0.12345,0.12345, when changed to 9,9, gives the largest number?
11
22
33
44
55
Answer: A
Concepts:place valuedecimal
Small hint:
Changing a digit in a higher place value raises the number by more
Big hint:
The leftmost digit 11 sits in the tenths place, the largest place value shown
Solution:
Changing a digit in the tenths place changes the number more than changing any digit farther to the right. The digit in the tenths place is 11.
Changing it gives 0.923450.92345, which is the largest possible result.
Thus, the correct answer is A .
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