Task: Question Answering
Input (English): Problem: p, q and r together earn rs. 1890 in 9 days. p and r can earn rs. 600 in 5 days. q and r in 7 days can earn rs. 910. how much amount does r can earn per day ?
Options: a. s. 40, b. s. 70, c. s. 90, d. s. 100, e. s. 120
Output (English): a