Question

The price of a car is decreased by 10 % and 20 % in two successive
years. What per cent of price of a car is decreased after two years?

Answer 1

Given,

The decrease amount in first year = 10%

The decrease amount in second year = 20%

To find,

The percentage of price decrease after two years.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

Let, the price of the car = Rs. x

Price after the discount of 1st year = x - (x×10/100) = x - x/10 = Rs. 9x/10

Price after the discount of 2nd year = 9x/10 - (9x/10 × 20/100) = 9x/10 - 9x/50 = 45x-9x/50 = 36x/50 = Rs. 18x/25

Amount of price decreased = x - 18x/25 = Rs. 7x/25

Percentage of price decreased = 100 × (7x/25 ÷ x) = 100 × (7x/25 × 1/x) = 100 × 7/25 = 28%

Hence, 28% price decreased in 2 years.