A floor is 79 m long and 6 m wide. If polishing costs 10 taka per m², what is the total cost?
Note
First find the area of the floor: 79 × 6 = 474 m². Cost = area × rate = 474 × 10 = 4740 taka. In cost problems, calculate the required area first, then multiply by the cost for one square unit. This avoids the common mistake of multiplying the perimeter by the rate. So the correct choice is 4740 taka.