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

Q: Problem: find the ratio in which rice at rs . 7.20 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 : 4 , d ) 4 : 5 , e ) none of these

A: b
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Q: Problem: of the 200 stamps in a collection , 90 are foreign and 60 are more than 10 years old . if 20 stamps are both foreign and more than 10 years old , how many stamps are neither foreign nor more than 10 years old ? 
Options: a ) 50 , b ) 70 , c ) 100 , d ) 130 , e ) 150

A: b
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Q: Problem: a grocery store bought some mangoes at a rate of 5 for a dollar . they were separated into two stacks , one of which was sold at a rate of 4 for a dollar and the other at a rate of 6 for a dollar . what was the ratio of the number of mangoes in the two stacks if the store broke even after having sold all of its mangoes ? 
Options: a ) 1 : 4 , b ) 1 : 5 , c ) 2 : 3 , d ) 3 : 2 , e ) 2 : 5

A:
d
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