A contractor estimated that one of his two brick layers would take 9 hours to build a certain wall and the other 10 hours. Howev
er, he knew from experience that when they worked together, 10 fewer bricks were laid per hour. Since he was in a hurry, he put both men on the job and found it took exactly 5 hours to build the wall. How many bricks did the wall contain?
If 25% is a fourth of the teacher staff, and this value is fifty, to find out how many teachers there are you just have to multiply by 4 to find out the 100%. So this means that 50*4= 200