Task: Question Answering
Input (English): Question: A solution of 80 litres contains oil and water in the ratio 10:x. If five litres of water is added to the solution, the ratio becomes 20:10, find the value of x?

 Option A: 4.1

 Option B: 4.9

 Option C: 4.7

 Option D: 5.7

 Option E: 8.5
Output (English): Option A