Question 927860
let h = his age in a particular yr
let s = sister's age
let b = brother's age
:
Write an equation for each statement
:
In a particular year my sister was twice as old as I was
s = 2h
 and I was twice as old as my brother.
h = 2b
or (get s and b in terms of h)
b = .5h
 The product of our ages was 216.
h*s*b = 216
replace s and b
h * 2h * .5h = 216
h^3 = 216
find the cube root
h = 6 yrs old
then
b = 3 yrs old
and
s = 12 yrs old
:
6 + 3 + 12 = 21