Question

R

Answer 1

Answer:

Ivy is 6 years old and Rose is 12 years old.

Step-by-step explanation:

To solve this problem, two variables are necessary since we have two unknown variables: Ivy's age and Rose's age.

Ivy's age will be $x$

and Rose's age will be $y$

"Ivy is half as old as her sister":

$x=\frac{y}{2}$

this will be our fist equation.

"In six years, Ivy will be two-thirds as old as Rose"

in six years Ivy will have $x+6$ years, and Rose will have $y +6$ years, so for this sentence we have the equation:

$x+6=\frac{2}{3}(y+6)$

this will be our second equation.

Substituting the value of x from the first equation into the second, and solving for y(Rose):

$\frac{y}{2}+6=\frac{2}{3} (y+6)\\\frac{y+12}{2} =\frac{2}{3} (y+6)\\y+12=\frac{4}{3} (y+6)\\3(y+12)=4(y+6)\\3y+36=4y+24\\36-24=4y-3y\\12=y$

Rose is 12 years old.

and Ivy (using the fist equation):

$x=\frac{12}{2}=6$

Ivy is 6 years old.