Question 1119821
x, sister's age
y, your age


-------------------------------------------
My current age is 4 times what my sister's age was 20 years ago. 
-----------------------------------------
{{{y=4(x-20)}}}



------------------------------------------
i am now twice as old as i was 20 years ago. ten years ago, my sister's age was 1/2 of my current age. 
-----------------------------------------
{{{system(y=2(y-20),x-10=(1/2)y)}}}


---------------------------------------------
ten years ago, my age was 1.5 times my sister's age. what is my current age?
-----------------------------------------------
{{{y-10=(3/2)(x-10)}}}




Use what you need.  Decide if your results make sense.



{{{highlight(y=40)}}}---------your age now
-
{{{highlight(x=30)}}}---------sister's age now