Two shopkeepers sell the same article at the same price for the same quantity. One gives $25\%$ discount; the other offers $25\%$ more quantity at the same price. From a customer's view, which is better?
"More quantity at same price" $\Rightarrow$ divide price by the quantity factor to get the effective price per unit.
cannot be determined
Take ₹100 for 4 units, so ₹25 per unit.
Since ₹18.75 is less than ₹20 per unit, the first shopkeeper's deal is better for the customer.