Abhijeet' is 50% less efficient than 'Vivek' and can

Solution

ATQ, Time taken by ‘Abhijeet’ to achieve the target alone = 8/0.25 = 32 days Time taken by ‘Vivek’ to achieve the target alone = 0.5 × 32 = 16 days Time taken by ‘Chirag’ to achieve the target alone = 16 + 4 = 20 days Let the total target achieved be 160 units Efficiency of ‘Abhijeet’ = 160/32 = 5 units/day Efficiency of ‘Vivek’ = 160/16 = 10 units/day Efficiency of ‘Chirag’ = 160/20 = 8 units/day For statement I: Time taken by ‘Abhijeet’ and ‘Chirag’ together to achieve 81.25% of the target = 0.8125 × (160/13) = 10 days Therefore, statement I is true. For statement II: Time taken by ‘Vivek’ and ‘Chirag’ to achieve 90% of the target together = 0.9 × (160/18) = 8 days Therefore, statement II is true. For statement III: Time taken by ‘Abhijeet’ is 12 days more than ‘Chirag’. Therefore, III is true.