Question

A mother has two children whose ages differ by 5 years. The sum of the squares of their ages is 97. The square of the​ mother's age can be found by writing the squares of the​ children's ages one after the other as a​ four-digit number. How old is the​ mother?

Answer 1

Answer:

41 years old.

Step-by-step explanation:

Let x represent age of younger child.

We have been given that a mother has two children whose ages differ by 5 years. So the age of older child would be $x+5$.

The sum of the squares of their ages is 97. We can represent this information in an equation as:

$x^2+(x+5)^2=97$

Let us solve for x.

$x^2+x^2+10x+25=97$

$2x^2+10x+25-97=0$

$2x^2+10x-72=0$

Divide both sides by 2:

$x^2+5x-36=0$

$x^2+9x-4x-36=0$

$x(x+9)-4(x+9)=0$

$(x+9)(x-4)=0$

$(x+9)=0 ; (x-4)=0$

$x=-9 ; x=4$

Since age cannot be negative, therefore, age of younger child is 4 years.

Age of older child would be $x+5\Rightarrow4+5=9$

Therefore, the age of older child would be 9 years.

We have been given that the square of the​ mother's age can be found by writing the squares of the​ children's ages one after the other as a​ four-digit number.

Square of 4: $4^2=16$

Square of 9: $9^2=81$.

Square of mother's age: $1681$

To find mother's age, we need to take positive square root of 1681 as:

$\sqrt{1681}=41$

Therefore, the mother is 41 years old.