Its original price was x dollars.

When they marked it up 50%, they took 50% of x dollars, which 
was .50x dollars and added that on to the original x dollars 
and got this

x + .50x dollars

which is 1.00x + .50x dollars or 1.50x dollars.

When they marked 1.50x dollars down 30% they took 30% of 1.50x 
dollars, which was .30(1.50x) or .45x dollars, and subtracted 
that from 1.50x dollars,
and got 

1.50x - .45x  dollars

which is 1.05x dollars for the final price.  Since we are
told that was 3360 dollars, then 





So the correct answer is choice (B) $3,200 

Edwin