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rarequeen917
Oct 2, 2008, 06:10 PM
I am a dummy in math can some one please give me some clue what to do

2.Solve the equation: x(x – 4) = 12

3.A boat travels 30 miles upstream against the current in the same amount of time it takes to travel 42 miles downstream with the current. If the rate of the current is 4 MPH, what is the rate of the boat in still water? Please think this one through carefully – it’s not a trick question, all the information is there.

4.A space ship lands on unexplored planet Zygos. A person who weighs 60 Kilograms (Kg) on Earth weighs 4.8 Kg on Zygos. How much would a piece of equipment weighing 1800 Kg on Earth weigh (in Kg) on Zygos? How much would that same person weigh on Earth in pounds?



7.The waiting time for a doctor’s appointment varies directly as the number of people in the waiting room (the more people, the longer the wait). If you must wait 45 minutes when there are 5 people ahead of you, how long will you expect to wait if there are 7 people ahead of you? 1 hour an 3 minutes

8.Solve this equation by the means of your choice: .

9.In our area, the ratio of sports cars to SUVs is 3/5. If there are 2000 SUVs, how many sports cars are there in our area?
I would say it is 6000 sport cars

10.Suppose 1/(2x – 4) + 1/(x – 2) = 3/2. What is x?

galactus
Oct 3, 2008, 05:08 AM
#7. Direct proportion is y=kx, where k is the constant of proportionality.

We are given x and y, so we can find k.

45=k(5), k=9

Now, plug 9 in for k and 7 in for x and find y. You're done. You will have to convert to hours and minutes.

pimp_mah_alpaka
Oct 3, 2008, 05:30 AM
No-one is a dummy. If you need help with a question in maths ask the teacher! This way you can learn and know what to do next time a question that relates to it pops up. Its never good to cheat!

galactus
Oct 3, 2008, 06:05 AM
3.A boat travels 30 miles upstream against the current in the same amount of time it takes to travel 42 miles downstream with the current. If the rate of the current is 4 MPH, what is the rate of the boat in still water? Please think this one through carefully – it’s not a trick question, all the information is there.


When the boat is rowing against the current its rate is 4-r.

When it is rowing with it, it is 4+r.

The times are equal and we know d/r=t.

\frac{30}{r-4}=\frac{42}{r+4}

Solve for r.

galactus
Oct 3, 2008, 08:27 AM
2.Solve the equation: x(x – 4) = 12

Just a simple quadratic, x^{2}-4x-12=0. Solve by factoring, quadratic formula, etc.



4.A space ship lands on unexplored planet Zygos. A person who weighs 60 Kilograms (Kg) on Earth weighs 4.8 Kg on Zygos. How much would a piece of equipment weighing 1800 Kg on Earth weigh (in Kg) on Zygos? How much would that same person weigh on Earth in pounds?

Similar to problem 7 I posted earlier. Use y=kx.


9.In our area, the ratio of sports cars to SUVs is 3/5. If there are 2000 SUVs, how many sports cars are there in our area?
I would say it is 6000 sport cars... Sorry,no. You're off by a factor of 5

The ratio is 3/5. There are 5 SUV's for every 3 sports cars.

\frac{3}{5}=\frac{x}{2000}




10.Suppose 1/(2x – 4) + 1/(x – 2) = 3/2. What is x?

\frac{1}{2(x-2)}+\frac{1}{x-2}=\frac{3}{2}

Find your LCD, multiply through to eliminate the fraction, then solve for x.

2(x-2)\cdot\frac{1}{2(x-2)}+2(x-2)\cdot\frac{1}{x-2}=2(x-2)\cdot\frac{3}{2}

Continue? See what I done?