Math Riddles

Question: can you make an equation by using only the no.-4,4,4,4 whose answer will be 20.

Question: In a house of Kardak's family each brother have a sisters as double as their brothers and each sister have brothers as same as their sister. How many brothers and sisters in Kardak's family ?

Question: When i was 4 my sister was half my age. Now I am 100. How old is my sister now?

Question: this is a 6 digit number. this number has two decimal places. there are no tenths or tens in this number. the tenths digit plus the hundredth digit equals 6. if you divide the thousands digit by 2 the answer is 2. the hundreds digit is the same as today's date. the units digit is half the hundredths unit.

Question: At low tide 14 rungs of a ship are above the water, the rungs are 15 centimeters apart. each 15 mins the water rises 15 centimeters. after 2 hours and 30 mins how many rungs are above the water?