Can anyone help me out with these problems?

jenzy569

New member
Joined
Jul 13, 2009
Messages
36
1. A rectangular garden has dimensions of 15 feet by 11 feet. A gravel path of uniform width is to be built around the garden. How wide can the path be if there is enough gravel for 192 square feet?

2. A business invests $8,000 in a savings account for two years. At the beginning of the second year, an additional $2,500 is invested. At the end of the second year, the account balance is $11,445. What was the annual interest rate?

3. The Hudson River flows at a rate of 5 miles per hour. A patrol boat travels 40 miles upriver, and returns in a total time of 6 hours. What is the speed of the boat in still water?

4. Do exponential functions only model phenomena that grow, or can they also model phenomena that decay? Explain what is different in the form of the function in each case.

5. True or false: The function "f(x) = 4x" grows four times faster than the function "g(x) = x". Explain.

6. What are the asymptotes of the functions "f(x) = 4x" and "g(x) = log5x"?

7. A cell divides into two identical copies every 4 minutes. How many cells will exist after 5 hours?

8. The level of thorium in a sample decreases by a factor of one-half every 2 million years. A meteorite is discovered to have only 8.6% of its original thorium remaining. How old is the meteorite?
 
jenzy569 said:
1. A rectangular garden has dimensions of 15 feet by 11 feet. A gravel path of uniform width is to be built around the garden. How wide can the path be if there is enough gravel for 192 square feet?
One for free. Then show your work.

Rule #1 - Name Stuff.
Name What?
What does it want? "How wide can the path be...?"
Name that.

P = Path Width

There you go.

\(\displaystyle (15 + 2P) \cdot ft \cdot (11 + 2P) \cdot ft\; - \;(11 \cdot 15)\;ft^{2} \, = \, \;192\;ft^{2}\) .......edited

Questions for you...

1) Why is it 2P and not just P?
2) What is the Domain of the solution? It should be obvious that P > 0, but is there an upper limit?
 
tkhunny said:
jenzy569 said:
1. A rectangular garden has dimensions of 15 feet by 11 feet. A gravel path of uniform width is to be built around the garden. How wide can the path be if there is enough gravel for 192 square feet?
One for free. Then show your work.

Rule #1 - Name Stuff.
Name What?
What does it want? "How wide can the path be...?"
Name that.

P = Path Width

There you go.

\(\displaystyle (15 + 2P) \cdot ft \cdot (11 + 2P) \cdot ft\; - \;(11 \cdot 15)\;ft^{2} \, = \, \;192\;ft^{2}\) .......edited

Questions for you...

1) Why is it 2P and not just P?
2) What is the Domain of the solution? It should be obvious that P > 0, but is there an upper limit?

I see I was gravelling the inside. Whoops! Good call.

As far as receiving no help, did you answer my questions?
 
Top