Maximum Chocolates | Puzzles for Interview - Interview Preparation PDF Download

Introduction

If you have 15 Rs, you can go to a shop and buy chocolates for 1 Rs each. But the shopkeeper also tells you that if you bring back 3 empty chocolate wrappers, he will give you another chocolate for free. So how many chocolates can you eat in total?

Solution

First, you can buy and eat 15 chocolates with your 15 Rs. This leaves you with 15 empty wrappers. You can return these 15 wrappers and get 5 more chocolates for free (since you have 5 sets of 3 wrappers). Now you have 5 more chocolates, but also 3 wrappers left over from each one you ate. You can return 3 of these wrappers and get another chocolate for free, and eat it. This leaves you with 2 wrappers. You can return these 2 wrappers along with another set of 3 wrappers and get one more chocolate for free.
Total number of chocolates:
So in total, you can eat 15 + 5 + 1 + 1 = 22 chocolates!

Conclusion

With just 15 Rs, you can eat 22 chocolates by using the shopkeeper's offer of giving a free chocolate for every 3 empty wrappers.