Movie Tickets

[nycmath]

A movie hall sold tickets to one of its shows in two denominations, 11 dollar and 7 dollar. A fourth of all those who bought a ticket also spent 4 dollar each on refreshments at the movie hall. If the total collections from tickets and refreshments for the show was 124 dollar, how many 7 dollar tickets were sold? Note: The number of 11 dollar tickets sold is different from the number of 7 dollar tickets sold.