A metal of 50000/77 kg/m3 is used to make the weights for measuring. But the dishonest shopkeeper purchases a tampered weight. The original weight should be a cylinder of 7 cm radius and 5 cm height. The tampered weight also looks same but inside the cylinder there is a hollow cylindrical region of 2.8 cm radius and 2.5 cm height. If honestly he could make 20% profit, what is the profit (%) he makes by dishonest method?
A metal of 50000/77 kg/m3 is used to make the weights for measuring. But the dishonest shopkeeper purchases a tampered weight. The original weight should be a cylinder of 7 cm radius and 5 cm height. The tampered weight also looks same but inside the cylinder there is a hollow cylindrical region of 2.8 cm radius and 2.5 cm height. If honestly he could make 20% profit, what is the profit (%) he makes by dishonest method? Correct Answer 30 10/23
Original volume of standard weight = πr2h
⇒ 22/7 × 72 × 5
⇒ 770 cm3
Volume of metal in the tampered weight = Original volume – Volume of cavity
⇒ 770 – 22/7 × 2.82 × 2.5
⇒ 708.4 cm3
% volume filled in tampered weight = 708.4/770 × 100
⇒ 92%
That is if he sells 100 grams, he actually sells only 92 grams
Let cost price of one gram be Rs. x.
Selling price = (100 + Profit%)/100 × Cost price
⇒ (100 + 20)/100 × x
⇒ 1.2x
∴ Profit% = (Selling price of 100 grams – Cost price of 92 grams)/Cost price of 92 grams × 100
⇒ (1.2x × 100 – x × 92) / (x × 92) × 100
⇒ 2800/92
⇒ 30 10/23%