Question

The water level in a water tank rises 20% when it is filled in the morning and falls 20% during the day what is the net rise or fall in the water level in the tank

Answer 1

let water in water tank is 100 litres
in morning tme:- water increase 20% so water level is now 120 litres
after using :- decrease 20% so water in tank =120-24=96 litres
hence 4% decrease water in the water tank .