let Cynthia's age be C, then Abigail's age A
since Abigail is 8 years older, her age A = C+8.
20 years ago Cynthia's she was C-20 and Abigail was A-20=3(C-20)
A-20=3C-60
A=3C-40
but we just said A=C+8
so 3C-40=C+8
2C=48
C=24
A=24+8=32
Cynthia's age is 24 and Abigail's age is 32
