The age of a father 10 years ago was thrice the age of his son. 10 years hence , the father's age will be twice that of his son. The ratio of their present age is = ?

• ক 9 : 5
• খ 7 : 3 ✅ সঠিক উত্তর
• গ 5 : 2
• ঘ 8 : 5