Question 997479
 A mother has seven children, the mean age of the children is 13 years 2 months.
 If the mother's age is added , the mean age will be 17 years 7 months.
 Find the mothers age?
:
convert the given ages to months
13 y 2m:  12*13 + 2 = 158 months
17 y 7m:  12*17 + 7 = 211 months
:
Let m the the mom's age in months
{{{(7(158) + m)/8}}} = 211
multiply both sides by 8
1106 + m = 8(211)
m = 1688 - 1106
m = 582 months which is 582/12 = 48.5; 48 yrs 6 months is Mom's age