In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Q: Problem: along a yard 414 metres long , 24 trees are palnted at equal distances , one tree being at each end of the yard . what is the distance between two consecutive trees 
Options: a ) 18 , b ) 19 , c ) 10 , d ) 11 , e ) 12

A: a
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Q: Problem: r is the set of positive even integers less than 20 , and s is the set of the squares of the integers in r . how many elements does the intersection of r and s contain ? 
Options: ['a ) none', 'b ) two', 'c ) three', 'd ) five', 'e ) seven']

A: c
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Q: Problem: a train travels from albany to syracuse , a distance of 100 miles , at the average rate of 50 miles per hour . the train then travels back to albany from syracuse . the total travelling time of the train is 5 hours and 24 minutes . what was the average rate of speed of the train on the return trip to albany ? 
Options: a ) 31.25 , b ) 30 , c ) 32 , d ) 34 , e ) 36

A:
a
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