oranges in a pile: powerprep

[tytyros]

a grocer stocked oranges in the pile. The bottom layer was rectangular with 3 rows of 5 orranges each, in the 2nd layer from the bottom each orange rested on the 4 oranges from the bottom layer , and in the 3rd layer each orange rested on 4 oranges from the 2nd layer. which of the following could be the maximum no of oranges in the 3rd layer ?
5,4,3,2,1

[bose]

imo 3. i just drew a pic and saw 2nd row has 8 and 1st row has 3. there might be a better way of doing this.

[tarkumar]

on top of m*n oranges (m-1) * (n -1) oranges can be places so total oranges in bottom most layer - 3 * 5, next layer will have 2 * 4 oranges and next 1 * 3 and no more oranges can be kept on top of 3 oranges in single row so answer should be 3

[mrudang1986]

according to me 3 is correct answer.

We can simply draw figure and identify that second column is having 8 and thus to rest on 8 we would be having 3.

[Praso]

tarkumar,
thats a good solution. i drew the pic, the same way bose did

[tarkumar]

got the generic rule for m * n where m >= n , the number of oranges at top layer = m - n +1

[Praso]

m-n+1? Hows it possible.
If there is a 9X8 in the bottom layer, can there be only oranges in the second layer from bottom? doesnt make sense to me...