Question

Ajay alone can complete a work in 10 days and Bittu alone can complete the same work in 15 days. Ajay starts the work alone and after three days Bittu joined him to complete the rest work. Then in how many days is required to complete the entire work?

A 7.2 days Correct Answer Incorrect Answer
B 6.7 days Correct Answer Incorrect Answer
C 5 days Correct Answer Incorrect Answer
D 12 days Correct Answer Incorrect Answer

Solution

Entire work efficiency of Ajay is 10 x 3 unit/day = 30 units  Bittu work efficiency is 15 x 2unit/day = 30units  ATQ,  Let no. of days taken by Ajay and Bittu together to complete the rest work be ‘x’ days. 3 × 3 + (3 + 2) × x = 30  5x = 21  x = 4.2 days Total days = 3 + 4.2  =7.2 days

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