Question

The Johnson twins were born four years after their older sister. This year, the product of the three siblings ages is exactly 3482 more than the sum of their ages. How old are the twins?

Answer 1

Explanation:

Let age of each twin be x

let age of sister be s

So we can write:

x + 4 = s

The product of the 3 siblings ages is 3482 more than sum. We can write:

`s*x*x=3482+(s+x+x)`

This can be simplified as:

`sx^2=3482+s+2x`

We replace s with "x + 4" and solve:

`(x+4)x^2=3482+x+4+2x\\x^3+4x^2=3486+3x\\x^3+4x^2-3x-3486=0\\x=14`

Note: To solve this cubic, we used technology

Thus, we can say the twins are 14 years old