Question

After availing two successive discounts of 20% each, Madhavi paid Rs 64 for a book. If she would have got only one discount of 20%, how much additional amount would she have paid?

Answer 1

Let the price of the book be ₹ x.

After the first 20% discount, the price of the book becomes

= x`(1 - 20/100)`

= x`(1 - 1/5)`

= `(4"x")/5`  ...........(i)

After another 20% discount, the price of the book becomes

= `(1 - 20/100)(4/5"x")`

= `(1 - 1/5)(4/5"x")`

= `(4/5)(4/5)"x"`

= `16/25"x"`

This price = ₹ 64  ....[Given]

∴ `16/25  "x" = 64`

∴ x = 4 × 25 = 100

Thus, Amount of the book after one discount

= `4/5 (100) = 80`   ...[from(i)]

∴ The additional amount that Madhavi would have paid = 80 – 64 = ₹ 16.