Question 1109307
Let{{{ a }}} = number of dogs
Let {{{ b }}} = number of cats
Let {{{ c }}} = number of mice
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{{{ a + b + c = 100 }}}
{{{ 10a + 3b + .5c = 100 }}}
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options:
a = 9
b = 3
c = 2
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a = 9
b = 1
c = 14
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a = 8
b = 6
c = 4
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a = 8
b = 1
c = 34
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a = 7
b = 9
c = 6
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a = 7
b = 1
c =  54
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a = 6 
b = 13
c = 2
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a = 6
b = 1
c = 74
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a = 5
b = 1
c = 94
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By trial and error, it looks like this is the answer
5 dogs
1 cat
94 mice
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Their may be other answers, also.
I couldn't use equations to solve because there
are 3 unknowns and only 2 equations