Hi All,
When you're dealing with "ratio data" in a DS question, it's actually really easy to prove if a pattern exists or not - just run through a few quick TESTs...
Here, we're told:
Adult tickets cost $5 each
Children's tickets cost $2 each
We're asked for the AVERAGE COST of all tickets sold yesterday.
Fact 1: The ratio of Children's tickets to Adult's tickets was 3:2 yesterday.
Some Test Takers can clearly see that this ratio IS enough information to say that Fact 1 is SUFFICIENT. Here's how you can quickly prove the consistency...
IF...
3 children
2 adults
3(2) + 2(5) = 16/5 = $3.20 average ticket price
6 children
4 adults
6(2) + 4(5) = 32/10 = $3.20 average ticket price
9 children
6 adults
9(2) + 6(5) = 48/15 = $3.20 average ticket price
With this ratio, the average is ALWAYS $3.20
Fact 1 is SUFFICIENT
Fact 2: 80 Adult tickets were sold
Here, we don't know the number of Children's tickets, so the average ticket price would change depending on THAT number. Again, here's the proof:
0 children
80 adults
0 + 80(5) = 400/80 = $5 average ticket price
80 children
80 adults
80(2) + 80(5) = 560/160 = $3.50 average ticket price
Fact 2 is INSUFFICIENT
Final Answer:
GMAT assassins aren't born, they're made,
Rich