The ratio between the present ages of M and N is 5 : 3. The ratio between M's age 4 years ago and N's age after 4 years is 1 : 1. What is the ratio between M's age after 4 years and N's age 4 years ago?
A2 : 1
B1 : 3
C4 : 1
D3 : 1
The ratio between the present ages of M and N is 5 : 3. The ratio between M's age 4 years ago and N's age after 4 years is 1 : 1. What is the ratio between M's age after 4 years and N's age 4 years ago?
A2 : 1
B1 : 3
C4 : 1
D3 : 1