Alam starts working on a job and works on it for 12 days and completes 40% of the work. Then Babu joins Alam and together they complete the rest of the work in 12 days. How long will it take Babu to complete the job if he works alone?
A. 24 days
B. 30 days
C. 45 days
D. 60 days
Explanation: আলম 40% complete করে 12 দিনে 100% complete করে \(\frac{12 \times 100}{40} = 30\) দিনে। সুতরাং একদিনে করে 1/30 অংশ। দুইজনে 60% complete করে 12 দিনে। 100% complete করে \(\frac{12 \times 100}{60} = 20\) দিনে। সুতরাং একদিনে করে 1/20 অংশ। বাবু একদিনে করে \((1/20-1/30) = 1/60\) অংশ। সুতরাং বাবু 60 দিনে কাজ complete করে। সঠিক Answer (D).
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