I have communicate with every parent about students’ test score and ran an extra session on Saturday 11/10/2012 to go over the tests.
Today we first cover the section for word problems leading to quadratic equations, question like find the number such that the sum of the number and its square is 156. We go from the given conditions to come up with a quadratic equation, solve it. With real world problem, we need to be care to pick the right answer as a quadratic equation can have two solutions, one is possible, the other can be impossible in the real world.
We move on to talk about rate, ratio and percentage, and the corresponding word problems.
Rate is used to describe how a quantity change with regard to another quantity. For example, a worker is paid $84 for 6 hours of work, we say that he is paid $14 for one hour, or at the rate of $14/h.
Ratio is used to compare the magnitude of two similar quantities. It indicates what fraction one quantity is of the other, or how many times one quantity is as much as the other. Here is an example: a sum of money is divided between X and Y in the ratio of 3:5. if X gets $x and Y gets $y, then we can write: x:y = 3:5, or x/y = 3/5, etc.
Percentage is a special fraction with one hundred as its denominator. For example, 15% = 15/100 = 0.15
There are quite some word problems involving rate, ratio, and percentage, and some of them can be challenging,. We talk about several examples in the classroom.
Homework:
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