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

[EX Q]: Problem: a 10 % stock yields 8 % . the market value of the stock is :
[EX A]: rs . 125

[EX Q]: Problem: a gambler has won 40 % of his 40 poker games for the week so far . if , all of a sudden , his luck changes and he begins winning 70 % of the time , how many more games must he play to end up winning 60 % of all his games for the week ?
[EX A]: 80

[EX Q]: Problem: a solution of 70 litres contains oil and water in the ratio 9 : x . if 6 litres of water is added to the solution , the ratio becomes 6 : 4 , find the value of x ?
[EX A]: