A rectangular swimming pool measures 20 meters by 10 meters. How wide must a concrete walk around the pool be if the walk is to cover an area of 124 square meters?
We have to assume that the walk must have the same width on each of the four sides of the pool. We often have unstated assumptions like this in a math problem. With a width of w, the area of the entire walk is 20w+20w+10w+10w+4w^2 (where w^2 is w squared), or 60w+w^2. This is 124 square meters, so we can solve for w using the Quadratic Formula.
Example #6: A man is nine times as old as his son. In nine years, he will be only three times as old as his son. How old are each now?
If the son's age is s, then the father's age is 9s. In 9 years, the son's age will be s+9, and the father's age will be 9s+9. The father's age will also be 3(s+9). So 3(s+9)=9s+9. We can solve for s, and then solve for s+9 (don't forget that part of the problem).
So this is why I have an job I don't care much about and no good prospects. I never wanted to get to know this math shit, in an engineering sense and I choose jobs to stay "hands on". I wonder if I could get it better the second time around? -m
A rectangular swimming pool measures 20 meters by 10 meters. How wide must a concrete walk around the pool be if the walk is to cover an area of 124 square meters?
ReplyDeleteWe have to assume that the walk must have the same width on each of the four sides of the pool. We often have unstated assumptions like this in a math problem. With a width of w, the area of the entire walk is 20w+20w+10w+10w+4w^2 (where w^2 is w squared), or 60w+w^2. This is 124 square meters, so we can solve for w using the Quadratic Formula.
Example #6: A man is nine times as old as his son. In nine years, he will be only three times as old as his son. How old are each now?
If the son's age is s, then the father's age is 9s. In 9 years, the son's age will be s+9, and the father's age will be 9s+9. The father's age will also be 3(s+9). So 3(s+9)=9s+9. We can solve for s, and then solve for s+9 (don't forget that part of the problem).
So this is why I have an job I don't care much about and no good prospects. I never wanted to get to know this math shit, in an engineering sense and I choose jobs to stay "hands on". I wonder if I could get it better the second time around? -m
ReplyDelete