SOLVE THIS!!!

[B333]

The square of Ajua's age six years ago is her age in six years time. Find her present age. (Hint it is NOT 4 and NOT 15). Thank you.

 

[john10]

10

 

[john10]

is it right?

 

[B333]

I have no idea!!! Can you tell me how you got that answer?

 

[RoaringInferno]

The square of Ajua's age six years ago is her age in six years time. Find her present age. (Hint it is NOT 4 and NOT 15). Thank you.

You can solve this pretty easily using a quadratic equation.
Assume Ajua's age as x years.
So Ajua's age 6 years ago was (x-6) years which, when squared, becomes (x-6)^2
Ajua's age 6 years later will be (x+6) years.
As per your question...
Square of Ajua's age 6 years ago = Ajua's age in 6 years time
(x-6)^2 = x + 6
Assuming you're familiar with the expansion of (a+b)^2
(x)^2 +2(x)(-6) + (-6)^2 = x + 6
x^2 -12x + 36 = x + 6
Solve this and you will get
x= 10, x= 3
Hope this helps.

 

[B333]

Thanks RoaringInferno. Much appreciated/

 

[B333]

Hold on. They're both positive numbers so how would you know what is her age? Would you take the 3 or the 10?

 

[B333]

Or would it just be 10 because if she were three then 6 years ago she's be -3 which isn't possible?

 

[RoaringInferno]

Or would it just be 10 because if she were three then 6 years ago she's be -3 which isn't possible?

Sorry I didn't clear that up in the first place.
You're right. We will reject x= 3 because when x=3, her age six years ago would be -3 which isn't possible. So 10's the correct answer as it's the only viable option that satisfies both of the equations we have made.