Question :
In an apple farm, there are a total of 10 baskets, each containing 10 to 20 apples. 9 baskets contain apples weighing 4 kg whereas 1 basket contains apples weighing 5 kg.
The problem is that someone has mixed the baskets and the farmer has lost track of the heavier one. You have a measuring scale and an empty basket.
You can weigh only once to find the basket with heavier apples. Tell us how ?
Solution :
What solution comes to your mind ?
Let us show you some light. You can mark the baskets from one to ten. Then draw out the same number of apples as the basket number as put it in the empty basket. That is, draw 1 apple from basket 1, 2 from basket 2 and so on until the final one. You now have 55 apples in the basket. Weigh it. If each of the boxes weighed exactly 4 kg apples, the total weight of the basket would be 220 kg. But since one of the baskets contains apples with 5 kg, the weight should be more. Subtract 220 from the final weight. For instance, if the total weight now comes to be 225 kg then the number you get is the extra weight of the 5 kg apples, i.e., the basket number of the 5 kg apples.
