If 12 boys earn Rs 840 in 7 days, what will 15 boys earn in 6 days?
Given,
∵ Earning of 12 boys in 7 days = Rs.840
∴ Earning of 12 boys in 1 day = 
∴ Earning of 1 boy in 1 day = 
∴ Earning of 1 boy in 6 days = 
Hence, Earning of 15 boys in 6 days = 60 × 15 = Rs. 900
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