The table show 1 2 3 4 5s prices and numbers of commodities bought.

Number of commodities (Q) 1 2 3 4 5
Prices (N) 5 10 X 20 Y
Determine X + Y.

There is not enough information given to determine X + Y. We know the prices for buying one commodity and buying five commodities, but we do not know the price for buying three or the price for buying two or four. Therefore, there are multiple possible values for X and Y that would satisfy the given information.