Question 1057600
If Linda and Jennifer's ages add to 25, there is no way that 18 years ago at least one of them, if not both, had a positive age.
Linda is x
Jennifer is y
x+y=25
x-18=2(y-18)
x-18=2y-36
x-2y=-18
-x+2y=18
x+y=25
3y=43
y=43/3
x=32/3
They add to 25
18 years earlier, their ages were negative
Therefore not possible.