A faulty weighing machine reads 1 kg when 900 gm is actually weighted on it. The shopkeeper marked the price of his goods by 10%, but unfortunately he was caught by the metrology department and then they ordered him to repair his weighing machine and gave punishment to sell the goods at 10% discount on cost price for a month. If each customer is now paying Rs. 20 for 1 kg, then before the raid . . . . . . . . amount they have paid for the same quantity. (Rounded off to two places of decimal)

Solution(By Examveda Team)

After getting caught = as a punishment giving 10% discount on cost price for every 1 kg and customer is paying Rs. 20 for 1 kg.
Therefore,
Actual cost price (for customer) = $$ = \frac{{20}}{{0.9}} = \frac{{200}}{9}$$
But shopkeeper before raid was selling at marked price which is 10% more than cost price $$ = 1.1 \times \frac{{200}}{9} = \frac{{220}}{9}$$
But this amount was before raid paid for 900 gm
So, actual amount paid for 1000 gm before raid $$ = \frac{{\frac{{220}}{9}}}{{900}} \times 1000 = {\text{Rs}}{\text{. }}27.16$$