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

[EX Q]: Problem: a student chose a number , multiplied it by 2 , then subtracted 138 from the result and got 102 . what was the number he chose ?
[EX A]: 120

[EX Q]: Problem: two numbers are in the ratio of 7 : 6 . if 18 be subtracted from each , they are in the ratio of 6 : 5 . find the numbers ?
[EX A]: 7,6

[EX Q]: Problem: the total number of digit used in numbering the pages of a book having 366 pages , is :
[EX A]:
990