Question 164507
2)Ryan was born 6 and one-fourth years after Alexander.The sum of their ages are 66 and eleven-twelfth years.How old are Alexander and Ryan?
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Man, they love these fractions, don't they
:
Let r = Ryan's age now
Let a = Alexander's age now
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Write an equation for each statement:
:
"Ryan was born 6 and one-fourth years after Alexander."
r = a - 6{{{1/4}}}
Convert to an improper fraction
r = a - {{{25/4}}}
Get rid of the fraction, mult by 4
4r = 4a - 25
or
4a - 4r = 25
:
"The sum of their ages are 66 and eleven-twelfth years."
a + r = 66{{{11/12}}}
convert to an improper fraction
a + r = {{{803/12}}}
Get rid of the fraction, mult by 12
12a + 12r = 803
:
Multiply eq (4a-4r=25) by 3 and add to the above equation
12a + 12r = 803
12a - 12r = 75
------------------adding eliminates r, find a
24a = 878
a = 36{{{14/24}}}
a = 36{{{7/12}}} is Alexander's age
:
Find r using equation: a + r = 66{{{11/12}}}
r = 66{{{11/12}}} - 36{{{7/12}}}
r = 30{{{4/12}}}
r = 30{{{1/3}}}; is Ryan's age
;
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Confirm our solutions using the original equation: r = a - 6{{{1/4}}}
30{{{4/12}}} = 36{{{7/12}}} - 6{{{3/12}}}

30{{{4/12}}} = 30{{{4/12}}}