Question 17540
For problems like these, you need to take powers of 2 as the amount that needs to go into the envelopes,
Starting from 0
2^0 =  1 so 1 goes into the first envelope
2^1 = 2          2nd Envelope
2^2 = 4         3rd envelope

So, let's see what all amounts we have
1
2
1+2 = 3
4
4+1 = 5
4+2 = 6
4+2+1 = 7

Now if you took 2^3 for the 4th evelope you would get more amounts. However can you find out what goes into the 10th envelope??