Correct Answer - Option 3 : 20%
Given:
The price of two books A and B is 3500 and 4400 respectively.
The price of A decreases by a certain %.
The price of B increased by the same percentage.
The ratio of A and B after this change is 35: 66.
Formula used:
Profit or Gain = Selling price – Cost Price
Loss = Cost Price – Selling Price
Profit percentage = (Profit/Cost Price) × 100
Loss percentage = (Loss/Cost price) × 100
Calculation:
Let x be the % with which A decrease and B increases.
ATQ,
{3500(100 – x)}/{4400(100 + x)} = 35/66
⇒ (100 – x)/(200 + 2x) = 1/3
⇒ x = 20
∴ Required percentage is 20%