TASK DEFINITION: In this task, you need to provide the correct option for a given problem on probability from the provided options.
PROBLEM: Problem: in how many ways can 21 books on english and 19 books on french be placed in a row on a shelf so that two books on french may not be together ?
Options: a ) 3990 , b ) 1540 , c ) 1995 , d ) 3672 , e ) none of these

SOLUTION: b

PROBLEM: Problem: given a bag with 2 red balls and 3 yellow balls , you randomly select one of them , in order . if the second ball you take is yellow , what is the probability that the first one was also yellow ?
Options: a ) 1 / 2 , b ) 1 / 5 , c ) 3 / 4 , d ) 1 / 3 , e ) 3 / 5

SOLUTION: a

PROBLEM: Problem: in how many ways can 7 boys be seated in a circular order ?
Options: a ) 110 , b ) 230 , c ) 720 , d ) 420 , e ) 680

SOLUTION:
c