a vendor bought toffees at 6 for a rupee. how many for a rupee must he sell to gain 20%?

A vendor bought toffees at 6 for a rupee. To gain 20%, he must sell 5 toffees for a rupee. Explanation:

• Cost price (CP) of 6 toffees = Rs. 1
• Therefore, CP of 1 toffee = Rs. 1/6
• To gain 20%, the selling price (SP) should be 120% of CP.
• SP of 1 toffee = 16×65=15\frac{1}{6}\times \frac{6}{5}=\frac{1}{5}61​×56​=51​ Rs.
• So, selling price of 1 toffee is Rs. 1/5, meaning 5 toffees can be sold for Rs. 1 to achieve a 20% gain.

Hence, the vendor must sell 5 toffees for a rupee to gain 20%