Official Solution: The table below shows the numbers of four pastry box types sold by a bakery in March and in April.
| - | March | April |
| Classic | 260 | 232 |
| Chocolate | 180 | 188 |
| Berry | 150 | 161 |
| Pistachio | 210 | 219 |
If the selling price of each box type stayed the same from March to April, did the bakery earn more revenue from the sales of these four box types in April than in March? Notice that the total number of boxes sold stayed the same:
March: \(260 + 180 + 150 + 210 = 800\)
April: \(232 + 188 + 161 + 219 = 800\)
So the only question is whether the shift in the mix of box types increased or decreased revenue.
From March to April:
Classic \(-28\)
Chocolate \(+8\)
Berry \(+11\)
Pistachio \(+9\)
So 28 fewer Classic boxes were sold, and those 28 sales were replaced by 28 sales of the other three box types combined.
(1) The Pistachio box was priced lower than each of the other three box types.
This is not enough.
For example, if the prices were Classic \(= 100\), Chocolate \(= 2\), Berry \(= 2\), and Pistachio \(= 1\), then the large drop in Classic sales would make April revenue lower than March revenue.
But if the prices were Classic \(= 2\), Chocolate \(= 100\), Berry \(= 2\), and Pistachio \(= 1\), then the increase in Chocolate sales alone would make April revenue higher than March revenue.
Not sufficient.
(2) The Classic box was priced higher than each of the other three box types.
Since the 28 lost Classic sales were replaced by 28 sales of
cheaper box types, total revenue must have decreased. So the answer is NO. Sufficient.
Answer: B