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

[Q]: Problem: a train running at the speed of 70 km / hr crosses a pole in 9 sec . what is the length of the train ?
[A]: 175 m


[Q]: Problem: you enter a weight loss challenge game and manage to lose 13 % of your body weight . for the final weigh in you are forced to wear clothes that add 2 % to your weight . what percentage of weight loss is measured at the final weigh in ?
[A]: 11.26 %


[Q]: Problem: an optometrist charges $ 150 per pair for soft contact lenses and $ 85 per pair for hard contact lenses . last week she sold 5 more pairs of soft lenses than hard lenses . if her total sales for pairs of contact lenses last week were $ 1,220 , what was the total number of pairs of contact lenses that she sold ?
[A]:
9