Difference between revisions of "1994 AJHSME Problems/Problem 12"

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<math>\text{(A)}\ 1990 \qquad \text{(B)}\ 1991 \qquad \text{(C)}\ 1992 \qquad \text{(D)}\ 1993 \qquad \text{(E)}\ 1994</math>
 
<math>\text{(A)}\ 1990 \qquad \text{(B)}\ 1991 \qquad \text{(C)}\ 1992 \qquad \text{(D)}\ 1993 \qquad \text{(E)}\ 1994</math>
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==Solution==
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<math>90=(3)(30)</math> which corresponds to March 30.
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<math>91=(7)(13)</math> which corresponds to July 13.
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<math>92=(4)(23)</math> which corresponds to April 23.
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<math>93=(3)(31)</math> which corresponds to March 31.
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<math>94</math> can only be factored into <math>(2)(47)</math>, which does not correspond to any date. The only year that is not lucky is <math>\boxed{\text{(E)}\ 1994}</math>.
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==See Also==
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{{AJHSME box|year=1994|num-b=11|num-a=13}}

Revision as of 23:41, 22 December 2012

Problem

A lucky year is one in which at least one date, when written in the form month/day/year, has the following property: The product of the month times the day equals the last two digits of the year. For example, 1956 is a lucky year because it has the date 7/8/56 and $7\times 8 = 56$. Which of the following is NOT a lucky year?

$\text{(A)}\ 1990 \qquad \text{(B)}\ 1991 \qquad \text{(C)}\ 1992 \qquad \text{(D)}\ 1993 \qquad \text{(E)}\ 1994$

Solution

$90=(3)(30)$ which corresponds to March 30.

$91=(7)(13)$ which corresponds to July 13.

$92=(4)(23)$ which corresponds to April 23.

$93=(3)(31)$ which corresponds to March 31.

$94$ can only be factored into $(2)(47)$, which does not correspond to any date. The only year that is not lucky is $\boxed{\text{(E)}\ 1994}$.

See Also

1994 AJHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 11
Followed by
Problem 13
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
All AJHSME/AMC 8 Problems and Solutions