An army’s recruitment process included N rounds of selection tasks. For the first A rounds, the rejection percentage was 60 percent per round. For the next B rounds, the rejection percentage was 50 percent per round and for the remaining rounds, the selection percentage was 70 percent per round. If there were 100000 people who applied for the army and 1400 were finally selected, what was the value of N? Choose the correct choice from the following answers.
A) 4  B) 5  C) 6  D) 8  E) 10
Since 70% is accepted and figure will be 1400 therefore in last stage tested/interviewed no. candidates should be 2000   So from here i will work for those two steps of decrements of 100000 candidates.   fastly i reduce 60% till it gets closer to our required 2000 candidates   step(1) 40000 accepted.   step(2) another 40%of 40000=16000 accepted.   here it is quiet observable that if we further deduct candidate by 60% it would change our probablity of easy going 2000 candidate.   so i would get to second stage of recruitment where 50 % is accepted   step(3) 50% of 16000=8000   step(4) 50% of 8000=4000   Step(5) 50% of 4000=2000...here we are done with total 5 steps   and last step of accepting 70% of 2000=1400(our target)   total 6 steps required.   Answer: 6
<result>C</result>
An army’s recruitment process included N rounds of selection tasks. For the first A rounds, the rejection percentage was 60 percent per round. For the next B rounds, the rejection percentage was 50 percent per round and for the remaining rounds, the selection percentage was 70 percent per round. If there were 100000 people who applied for the army and 1400 were finally selected, what was the value of N?