Can someone help me understand how to approach this revenue comparison DS question? The statements seem related but I can’t figure out if either is sufficient.?

Question

Yesterday Bookstore B sold twice as many softcover books as hardcover books. Was Bookstore B’s revenue from the sale of softcover books yesterday greater than its revenue from the sale of hardcover books yesterday?

1. The average (arithmetic mean) price of the hardcover books sold at the store yesterday was $10 more than the average price of the softcover books sold at the store yesterday.

2.  The average price of the softcover and hardcover books sold at the store yesterday was greater than $14.

Mansih K · Accepted Answer

Statement 2 says the average price across all books is more than $14. So: (s * S + h * H) / (s + h) > 14
We already know s = 2h. Let&rsquo;s plug that in: (2h * S + h * H) / (3h) > 14 &rarr; (2S + H)/3 > 14 &rarr; 2S + H > 42
Now use Statement 1: H = S + 10 So: 2S + (S + 10) > 42 &rarr; 3S > 32 &rarr; S > 10.67 That means softcover books are priced over $10.67, and hardcover books are over $20.67 Multiply by quantities: softcover revenue = 2h * S, hardcover = h * H With these values, 2h * S > h * H ends up being true
So when you use both together, it works. Answer is C &mdash; only sufficient when combined.

V Ritik · Answer

The question is whether softcover revenue (s * S) is greater than hardcover revenue (h * H), and we know s = 2h.
Statement 1 says H = S + 10. So hardcovers cost $10 more on average. Try plugging in numbers: If h = 10 &rarr; s = 20 (since s = 2h) If S = $10 &rarr; then H = $20 Softcover revenue = 20 * 10 = 200 Hardcover revenue = 10 * 20 = 200 &rarr; Equal revenue
But if S = 15, then H = 25 Softcover = 20 * 15 = 300 Hardcover = 10 * 25 = 250 &rarr; Now softcover > hardcover
So Statement 1 alone isn&rsquo;t enough. The revenue comparison depends on the price.

Can someone help me understand how to approach this 'revenue comparison' DS question? The statements seem related but I can’t figure out if either is sufficient.?