Mrs. Brown is 20 years old than her daughter.Five years ago,she was 3 times as old as her daughter.How old is her daughter? Can u tell me please Thank You

Sri

2. Originally Posted by sri340
Mrs. Brown is 20 years old than her daughter.Five years ago,she was 3 times as old as her daughter.How old is her daughter? Can u tell me please Thank You

Sri
Age of Mrs. B today: y
Age of the daughter today: x

From the question you know:

$\displaystyle x+20=y$

$\displaystyle y-5=3(x-5)$ ..... That's the situation 5 years ago. Be aware that the daughter was 5 years younger too!

This is a system of simultaneous equations. Solve this system of equations for x and y. (Use substitution method here)

I've got: (x, y) = (15, 35)

3. $\displaystyle B = Mrs. Brown$
$\displaystyle D = Daughter$

$\displaystyle D+20 = B$
$\displaystyle 3D = B$
$\displaystyle D + 20 = 3D$
$\displaystyle 20 = 2D$
$\displaystyle 10 = D$

But this situation was 5 years ago so...

$\displaystyle D + 5 = Age$
$\displaystyle 10 + 5 = 15$