Official Solution:If Richard is 3 years younger than his sister, how old is Richard? Let's assume Richard's age is \(r\) and his sister's age is \(s\). We are given that \(r = s - 3\) and asked to find the value of \(r\).
(1) Two years ago, Richard's sister was twice as old as Richard.
Given: \(s-2 = 2(s - 3 - 2)\). Solving for \(s\), we get \(s = 8\). Therefore, \(r = s - 3 = 8 - 3 = 5\). Sufficient.
(2) If Richard's sister had been born 2 years earlier, she would currently be twice as old as Richard.
If Richard's sister were born 2 years earlier, her age would be \(s + 2\) years now. So, \(s + 2 = 2(s - 3)\). Solving for \(s\), we get \(s = 8\). Therefore, \(r = s - 3 = 8 - 3 = 5\). Sufficient.
Answer: D