sunnymon
Karishma, but doesn't it also mean assuming otherwise - that tickets for both categories were purchased definitely. It is not given in the question stem that tickets for both categories (Adult and Children) were purchased. Statement 2, in my view, should also be self sufficient to answer the question (keeping no assumptions in mind).
VeritasPrepKarishma
Ace1144
hey champs... the OA: is A
still it looks like if hannah purchased 4 child tickets only, than the avg would of been the price of the ticket...
so b would of been sufficient...
but OA says A
You would be assuming that she purchased no adult's ticket if statement 2 were to be sufficient. But it is not given that she purchased no adult tickets or 'only children's tickets'. You cannot assume this is DS questions. Statement 2 only tells you how many children's tickets she purchased. It gives you incomplete information.
Statement 1 alone is sufficient since it tells you the ratio of the number of adult's tickets and children's tickets. With this ratio, you can easily find the average.
You are absolutely not assuming that she must have purchased tickets of both types.
The question is: What is the average price of the tickets she purchased.
What you know from stmnt 2: She purchased 4 children's tickets
How will you answer?
You will say that if she purchased no adult tickets, the average price is $24. If she did purchase adult's tickets too, the avg price is higher. Did you get a definitive unique value for the average price? No. This means this statement is not sufficient alone.
This sufficiency condition is the basic concept of DS questions which you must understand very properly to do well in DS.