Question 1129885
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Let the man's age in years be x.<br>
His grandson's age in months is the same as the man's age in years.  Since there are 12 months in a year, the grandson's age in years is x/12.<br>
His daughter's age in weeks is the same as his grandson's age in days.  Since there are 7 days in a week, the daughter's age is 7(x/12).<br>
The sum of their ages is 120 years:<br>
{{{x + x/12 + 7x/12 = 120}}}
{{{(12x+x+7x)/12 = 120}}}
{{{20x = 1440}}}
{{{x = 72}}}<br>
ANSWER: The man's age is 72 years.<br>
The problem doesn't ask for the ages of his daughter and grandson; they are x/12 = 6 for the grandson and 7x/12 = 42 for the daughter.  As a check, see that 72+42+6 = 120, as required.