How can you weight from 1kg to 40 kg with the help of four weight box?

It is normal to take the first weight equal to 1 kg.

So we can measure up to 1 kg.

Now the logic thing would be to take the second weight equal to 2 kg.

But we can skip the 2 kg and take the second weight equal to 3 kg, because by puting the first weight (=1 kg) on the other side of the balance, we can measure 2 kg.

By puting the first and the second weight together, we can measure up to 4 kg as well

Now the logic thing would be to take the third weight equal to 5 kg.

But we can skip the 5 kg and take the third weight equal to 9 kg, because by puting the first weight and second weight together (=4 kg) on the other side of the balance, we can measure 5 kg.

By puting the first and the second and the third weight together, we can measure up to 13 kg as well.

Using the same logic, the fourth weight must be equal to 27 kg.

In case we had only a two weight box, the weights should be 10 ad 30 kg, and we could measure 10, 20 (=30-10), 30 and 40 kg.

thanks for the explanation...

i happened to find another answer to this question.

i divide the 40kg weight into 4 parts of weights 2,6,7,25kgs respectively.

I'll be able to make numbers from 1 to 40 using these 4 numbers using + and - operations

7-6 =1

7+2-6 =3

6-2 =4

7-2 =5

6+2 =8

7+2 =9

25-7-6-2 =10

7+6-2 =11

25-7-6 =12

7+6 =13

25-7-6+2 =14

7+6+2 =15

25-7-2 =16

25-6-2 =17

25-7 =18

25-6 =19

25+2-7 =20

since i have proved it to be working for 1 to 20 it will also work for 21 to 40.