Question 841428
m = age of the man (current age)


g = age of the girl (current age)



"A man is three times a girls age" ----> {{{m = 3g}}}



"In 21 years, he will only be twice her age" ----> {{{m+21 = 2(g+21)}}}


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{{{m+21 = 2(g+21)}}}


{{{3g+21 = 2(g+21)}}}


{{{3g+21 = 2g+42}}}


{{{3g = 2g+42-21}}}


{{{3g-2g=42-21}}}


{{{g=21}}}


The girl is currently 21 years old.


{{{m = 3g}}}


{{{m = 3(21)}}}


{{{m = 63}}}


The man is currently 63 years old.