The task is to generate the correct answer for a given math problem.

[Q]: Problem: virginia , adrienne , and dennis have taught history for a combined total of 96 years . if virginia has taught for 9 more years than adrienne and for 12 fewer years than dennis , for how many years has dennis taught ?
[A]: 4


[Q]: Problem: the ratio of the radius of two circles is 1 : 3 , and then the ratio of their areas is ?
[A]: 1 : 9


[Q]: Problem: a semicircular shaped window has diameter of 63 cm . its perimeter equals
[A]:
162', 'b ) 766', 'c ) 298', 'd ) 277', 'e ) 198'