A bag contains 120 marbles. Some are red the rest are black. There are 19 red marbles for every black marble. How many red marbles are in the bag?

With finding limits of multi variable !

Asquare and an equilateral triangle have the same perimeter. each side the triangle is 4 inches longer than each side of the square. what is the perimeter of the square

The architect's side view drawing of a saltbox-style house shows a post that supports the roof ridge. the support post is 8 ft tall. the distance from the front of the house to the support post is less than the distance from the post to the back of the house. how far from the front of the house is the support post positioned?