Answer: a) 91 pins b) No.
Step-by-step explanation:
Since we have given that
Number of final bowling score of his friend = 105
Number of final bowling score of him be 'x'.
According to question, his final bowling score is 14 pins less than his friends final score, it becomes,

a) the final score of his is 91 pins.
b.) Your friend made a spare in the tenth frame. Did you? Explain.
No, as his friend has 14 pins more than him, so, he could not do this.
Hence, a) 91 pins b) No.