it depends on what fuel you're using, the weight of fuel in your tank, the heating value of your fuel, the maximum output of your burner or burners, and the utilization factor of each or more burners used.
for example, if you're using propane, which i normally do for my grill, the typical amount of propane in a tank is 15 lbs fully loaded. the heating value of propane is 21,600 btu per lb. the maximum heating output of my grill is around 30k btu per hour. for your household burner in a sinkie flat, it should be not more than 20k btu per hour. your utilization factor of each burner should be about 50% as one normally doesn't turn on full blast unless you need wok hei to cook up chilli crab.
usage time of your tank, if it's full and fuel is propane, is (15 lbs x 21,600 btu/lb) / (20,000 btu/hr x .5) = 32.4 hrs. usage time of your tank, if it's half full, is 16.2 hrs. to find out how full your tank is, boil a cup of water and slowly pour it over the side of your tank. after a while, feel the side of your tank where the water is poured and mark the point where it is cold on one half and warm on the other. visually from the mark, you can determine how much the tank is still filled with liquefied gas.
if you take 30 mins to cook per meal, your (full) tank will last 64.8 meals. your half tank will last 32.4 meals.
my grill uses a max heating output of 30k btu per hr and utilization factor of 50%. my usage time for a full tank is 21.6 hrs.