Anonymous on "in surat, every theatre, products are sold on more than MRP price"

hi , i live in surat, we have theatres , which shell products like cold drinks , water, snacks etc, more than MRP price, cinepolis, raj hans , etc all are doing same thing, is this by rule????
Is there any law that gives them right to sell products more than MRP value??
Like cinapolis sells water bottle of 12 rs MRP on 30 rs
it's value about2.5 times . Noone see MRP , people just take it , buy it , no complain , i'm very surprised, why this is happening???