Correct Option (B)
Let the original marked price of one mobile handset be 'x'.
Rakesh possessed an amount of money equivalent to the cost of 8 mobile handsets at their original marked price. Therefore, the total amount Rakesh had was 8x.
With this amount, Rakesh was able to purchase 10 mobile handsets due to a discount. This means the selling price of 10 handsets was 8x.
The original marked price for 10 mobile handsets would have been 10x.
The total discount offered on these 10 handsets is the difference between their original marked price and their selling price:
Discount amount = 10x - 8x = 2x.
To calculate the discount percentage, the formula is (Discount Amount / Original Marked Price of the items purchased) × 100:
Discount % = 10x2x×100=20%
Incorrect Options:
Options A (15%), C (25%), and D (30%) are incorrect. The calculation derived from the problem's conditions, where the money for 8 handsets allows the purchase of 10 handsets, precisely yields a 20% discount. These alternative percentages do not align with the described transaction.