Task: Question Answering
Input (English): Problem: in what ratio must a grocer mix two varieties of pulses costing rs. 15 and rs. 20 per kg respectively so as to get a mixture worth rs. 16.50 kg ?
Options: a. 7: 3, b. 3: 7, c. 4: 6, d. 5: 7, e. 8: 9
Output (English): a