In this task, you need to provide the correct option for a given problem from the provided options.

Problem: solution a is 20 % salt and solution b is 70 % salt . if you have 30 ounces of solution a and 60 ounces of solution b , in what ratio could you mix solution a with solution b to produce 50 ounces of a 50 % salt solution ? 
Options: a ) 6 : 4 , b ) 6 : 14 , c ) 2 : 3 , d ) 4 : 6 , e ) 3 : 7
c

Problem: there are 680 students in a school . the ratio of boys and girls in this school is 3 : 5 . find the total of girls & boys are there in this school ? 
Options: a ) 425 , b ) 345 , c ) 375 , d ) 380 , e ) 400
a

Problem: find the ratio in which rice at rs . 10.0 a kg be mixed with rice at rs . 5.70 a kg to produce a mixture worth rs . 6.30 a kg ? 
Options: a ) 1 : 3 , b ) 2 : 3 , c ) 3 : 5 , d ) 4 : 5 , e ) none of these

c