Answer:
Today Sally is 28 years old and her son is 10
Explanation:
x= Sally's Age; y= Sally's son age
Sally is 18 years older than her son
x-y=18
And she was three times older
x=3y
Substituting and solving:
3y-y=18
2y=18
Last year they were:
y=9
x=27
This year
y+1=10 ; x+1=28