Question 472730
Half of Henry's age added to 1/3 of Daisy's age is 11 years, 
6 years from now the sum of their ages will be 40 years.
 How old is each?
:
Let h = Henry's age
Let d = Daisy's age
:
Write an equation for each statement:
:
"Half of Henry's age added to 1/3 of Daisy's age is 11 years,"
{{{1/2}}}h + {{{1/3}}}d = 11
Get rid of the fractions, multiply eq by 6, results:
3h + 2d = 66
: 
"6 years from now the sum of their ages will be 40 years."
(h+6) + (d+6) = 40
h + d + 12 = 40
h + d = 40 - 12
h + d = 28
h = (28-d); we can use this for substitution
:
Replace h with (28-d) in the 1st equation
3(28-d) + 2d = 66
84 - 3d + 2d = 66
-3d + 2d = 66 - 84
-d = -18
d = 18 yrs is Daisy's age
then
h = 28 - 18
h = 10 yrs is Henry's age
:
:
Check solutions in the 1st statement
"half of Henry's age added to 1/3 of Daisy's age is 11 years,"
 {{{1/2}}}(10) + {{{1/3}}}(18) = 11
5 + 6 = 11