Question 349051
tom = x
Sally =y
...
10 years later
tom = x+10
sally = y+10
...
x+10 = 2(y+10)
x+10 =2y+20
x-2y=10....................1
8 years ago 
tom's age = x-8
sally's age = y-8
...
x-8=5(y-8)
x-8 = 5y-40
x-5y-40+8
x-5y=-32....................2
multiply equation by -1 and add to 2
-x+2y+x-5y=-10-32
-7y=-42
/7
y=-42/-7
y= 6 years = Sally's age now
...
...
plug value of y in equation 1
x-2*6=10
x-12=10
x= 22 tom's age now
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