Stmt 1 is obviously insufficient, as we don't know individual price for each sweater.

Stmt 2 alone is not sufficient either, since there's no total sales.

Combine stmt 1 and 2, AND condition from question stem, we know:
- price increased $30 from cost;
- price increased 50% from cost;
- total sales is $270.

So each sweater's cost is $60, sales price is $90, and 3 pieces were sold.

Answer is C.

Selling price = Cost + Profit
Profit = $30

Statement 1:
Total revenue = selling price x quantity sold

we don't know the selling price of each sweater, so insufficient.

Statement 2:
Selling price = 1.5 x Cost
So,
1.5 x cost = cost + profit
0.5 x cost = profit
0.5 x cost = 30
cost = 60

but we still can’t work out the quantity sold with knowing the total revenue.

Both statements together:
we know the cost, so selling price = $60 + $30 = $90.
and we know the total revenue = $270

So total quantity sold = total revenue/selling price

Sufficient. Choose C.

-BM-