A retailer orders u units of an item for which he pays d dollars. However, he mistakenly receives u - 3 items. How much was he overcharged, in terms of d and u?
A. 3d - u
B. 3du - 9
Say the retailer ordered u = 4 items for d = 4$ (1$ per item). Thus:
He received 4 - 3 = 1 unit for 4$, which is 3$ more than the item actually costs.
Now, plug u = 4 and d = 4 into the answer choices to see which one yields 3. Only C fits: (3d)/u = (3*4)/4 = 3.
Hope it's clear.
Please help me understand where am i going wrong ..
Amount per items actually recieved = d/u-3
Amount per items to be recieved = d/u
Overcharged amount = d/u-3 - d/u = 3d/u(u-3)