Task: Question Answering
Input (English): Problem: xavier, yvonne, and zelda each try independently to solve a problem. if their individual probabilities for success are 1 / 3, 1 / 2 and 5 / 8, respectively, what is the probability that xavier and yvonne, but not zelda, will solve the problem ?
Options: a. 1 / 16, b. 7 / 8, c. 9 / 64, d. 5 / 64, e. 3 / 64
Output (English): a