1993 AMC 8 Problem 12

Attempt Problem 12 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.

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12.

If each of the three operation signs, +,,×,+, -, \times, is used exactly once in one of the blanks in the expression

5x4x6x35 \, \underline{\phantom{x}} \, 4 \, \underline{\phantom{x}} \, 6 \, \underline{\phantom{x}} \, 3

then the value of the result could equal

99

1010

1515

1616

1919

Answer: E
Concepts:order of operationscasework

Difficulty rating: 890

Solution:

The six arrangements give 5×4+63=23,5 \times 4 + 6 - 3 = 23, 5×46+3=17,5 \times 4 - 6 + 3 = 17, 5+4×63=26,5 + 4 \times 6 - 3 = 26, 54×6+3=16,5 - 4 \times 6 + 3 = -16, 5+46×3=9,5 + 4 - 6 \times 3 = -9, and 54+6×3=19.5 - 4 + 6 \times 3 = 19.

The only value among the choices is 19.19.

Thus, the correct answer is E .

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