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