A household's monthly electricity charge is: first units at Rs. 10 per unit, next units at Rs. 20 per unit and every unit after at Rs. 30 per unit. Find the charge for units.
Answer and explanation
Correct answer: D. Rs. 1,800
- Step 1: First units: . Next units: .
- Step 2: Remaining units: . Total .
Answer
Rs. 1,800.
Why not the others: Rs. 900 is what you get if you charge every unit at the first rate. Rs. 2,700 is what you get if you charge every unit at the top rate. Rs. 1,500 is what you get if you ignore the third rate.
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