Question

The sum of the ages of Juwan and Christy is 92 years. 10 years ago, Juwan's age was 3 times Christy's age. How old is Juwan now?

Answer 1

You can use simultaneous linear equations in two variables to solve this word problem.

Let Juwan's age be
$x - years$
and Christy's age be
$y - years$
Let us sum their ages and equate it to 92

$x + y = 92 - - - (1)$
Ten years ago, Juwan's age was
$(x - 10)years$
and Christy's age was
$(y - 10)years$
By then Juwan's age was 3 times Christy's age
$(x - 10) = 3(y - 10)$
Expand and simplify,

$x - 10 = 3y - 30$
$x = 3y - 20 - - (2)$

Put equation (2) in equation (1)
$3y - 20 + y = 92$
$4y = 112$
$y = 28$
$x = 3(28) - 20 = 64$
Juwan is 64 now