Half of your baseball cards collection got wet and was ruined. You bought 19 cards to replace some that were lost. How many did you begin with if you now have 45

Consider the set of all four-digit positive integers less than 2000 whose digits have a sum of 24. what is the median of this set of integers?

Helll ! 1,400 tons of wheat of two different varieties was delivered to the silo. when processing one variety, there was 2% of waste and 3% during the processing of the second variety of wheat. after the processing, the amount of remaining wheat was 1,364 tons. how many tons of each variety of wheat was delivered to the silo?

Which of these figures must be a rectangle?