[quote="Bunuel"]

The table above shows quantities of the mobile phone models sold by a retailer. If prices did not change between 2003 and 2004, was the company’s total revenue from sales of these models in 2004 greater than its total revenue from sales of these models in 2003?
(1) Model A was the most expensive phone.
(2) Model C was the least expensive phone.
Kudos for a correct solution.Difference btw the mobile sales for each year is:
A : -15
B : 5
C : 10
Hence, the total number of phones sold by retailer is same each year. Hence to find the difference in revenue, the prices of each model is needed.
St 1: Model A is the most expensive phone but Model A is the phone which has sold least in 2014, compared to 2013. Cost of B and C has to be lower than A. Hence loss incurred by Model A cannot be compensated by Model B and C. Hence the revenue in 2014 will be lower than 2013.
Sufficient.
St 2: Model C is the least expensive phone. If Model A is Most expensive phone, then there will be a loss in revenue. But if Model B is the Most Expensive phone, then there will be gain in the revenue. Plugin numbers to check this. (A = 10, B = 9, C=8 and A = 10, B=50, C = 8 for the two cases). Hence No Sufficient.
Statement 1 alone is sufficient.
Option A.