Raghu bought toffees at 10 for a rupee. How many for a rupee must he sell to gain 400%?

Given:

Cost price of 10 toffees = 1 rupee

Gain = 400%

Formula Used:

Selling price = Cost price × (1 + Gain%)

Calculation:

Let the cost price of each toffee be 1/10 rupee.

Gain% = 400%

Selling price of each toffee = Cost price × (1 + Gain%)

Selling price of each toffee = (1/10) × (1 + 400/100)

Selling price of each toffee = (1/10) × (1 + 4)

Selling price of each toffee = (1/10) × 5

Selling price of each toffee = 1/2 rupee

To find how many toffees he must sell for 1 rupee:

Number of toffees = 1 / (1/2)

Number of toffees = 2

Raghu must sell 2 toffees for a rupee to gain 400%.