Robin's average (arithmetic mean) test score on 9 tests is 82. What must be Robin's score on a 10th test for his average score on the 10 tests to be 83?  Choose the correct choice from the following choices.
A) 92
B) 82
C) 72
D) 62
E) 52

Rationale: ( 9 * 82 + x ) / 10 = 83 x = ( 10 * 83 ) - ( 9 * 82 ) x = 830 - 738 total score required 830 - 738 = 92 correct answer is a
Answer: A