AboutChen Min Expertise All the conceptual questions except for probabilities and statistics are welcomed.
I am good at answering your algebra (including logarithm, functions, trigonometry) and geometry questions.
I can also provide to you a firm understanding into calculus and other mathematical ideas and concepts.
You can either ask questions in English or Chinese.
Important:Please avoid asking me questions related to economics.After all, I am only a secondary school student
Experience A lot of participation in Math Olympiad Competition with numerous awards (Not always gold, though)
Expert: Chen Min Date: 5/5/2008 Subject: application of quadratic equations
Question 1. Some students planned for a get-together. The budget for food was $5... Five of the students failed to come because of the distance and therefore the cost of food for each member increased by $5. How many students attended the get-together?
2. Steve traveled 600 miles at a certain speed. Had he gone 20mph faster, the trip would have taken 1 hour less. Find the speed of his vehicle.
3.Rita rows 12 km upstream in 3 hours. The speed of her boat in still water is 9 km/hr. Find the speed of the stream.
Answer 1.Assume there were x students to come in the plan,
the total food price = 5x
the actual number of students = x-5
the total food price = 10(x-5)
as the total food price does not change,
5x = 10(x-5)
x = 10....quadratic???
2.Assume the speed is v mph,
600/v ```````his time on the trip
600/(v + 20)``````````his expected time on trip
1`````````the difference in time taken.
Hence 600/v = 600/(v+20) + 1
Simplify it, vē+20v-12000 = 0
Factorise it, (v+120)(v-100) = 0
As v must be positive, v=100
3.Assume he's rowing in still water, then in 3 hrs, he should've
advanced 3*9 = 27km
The water opposing him "dragged" him 27-12 = 15km
The speed of water is 15/3 = 5km/h
(This question is not about quadratic equation, I reckon...)
