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Question

The ratio of number of days taken by Arjun and Bheem to complete a work individually is 7:8 and the ratio of number of days taken by Bheem and Chinky to complete a work individually is 6:7 and the ratio of number of days taken by Chinky, Danny, Elli and Finn to complete a work individually is 28 : 30 : 35 : 40. Arjun takes 21 days to complete a work individually.

Arjun & Chinky together start work and do it for 10 days and rest work is completed by Danny & ‘X’ together in 4 days. Then, in how many days ‘X’ alone can compete the work?

A 100 days Correct Answer Incorrect Answer
B 125 days Correct Answer Incorrect Answer
C 110 days Correct Answer Incorrect Answer
D 120 days Correct Answer Incorrect Answer
E none of these Correct Answer Incorrect Answer

Solution

ATQ, we can say that Efficiency of X = ‘e’ unit/day  10 × (40 + 30) + 4 × (28 + ‘e’) = 840  10 × 70 + 4(28 + ‘e’) = 840  4(28 + ‘e’) = 840 – 700  4(28 + ‘e’) = 140 28 + ‘e’ = 140/4  28 + ‘e’ = 35 ‘e’ = 35 – 28  ‘e’ = 7 unit/days  X alone complete the work in  = 840/7  = 120 Days

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