SOLUTION: Urgent request. Can you help me solve this problem: 1) The concentration of salt in Lake Ontario doubles every 7.25 years. If the current levels are 312.5 parts per million, a) F

Question 204822: Urgent request. Can you help me solve this problem:
1) The concentration of salt in Lake Ontario doubles every 7.25 years. If the current levels are 312.5 parts per million, a) Find an expression for the concentration of salt in Lake Ontario after n years.
b) The concentration levels of salt in the Dead Sea are 10 000 parts per million. How long will it take for the concentration of salt to reach these levels in Lake Ontario?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
1) The concentration of salt in Lake Ontario doubles every 7.25 years.
If the current levels are 312.5 parts per million,
a) Find an expression for the concentration of salt in Lake Ontario after n years.
f(n) =
:
b) The concentration levels of salt in the Dead Sea are 10 000 parts per million.
How long will it take for the concentration of salt to reach these levels in Lake Ontario?
:
f(n) = 10000
:
= 10000
:
Divide both sides by 312.5
=
:
= 32
:
32 = 2^5 so we can write it:
= 2^5
therefore
= 5
n = 5 * 7.25
:
n = 36.25 yrs
:
:
Check solution on a calc: enter 312.5 * = 10000

RELATED QUESTIONS
Hi! Please help me to solve this: Enough salt was added to 30kilos of a 10% salt... (answered by ramkikk66)

Please help me find the answer of this word problem: Nikki added 25ml of water to... (answered by scott8148)

A survey showed that the ratio of telephones to people in the world was 1:8. Of the... (answered by ankor@dixie-net.com)

What is the percentage error if I use a value of 3/1/7 for pie? I am having a great... (answered by stanbon)

URGENT CAN SOMEONE HELP ME ON THIS PROBLEM (answered by Alan3354,mouk)

Please help me solve this problem: The number of bacteria in a certain culture doubles... (answered by Alan3354)

What is the percentage error if I use a value of 3/1/7 for pie? I know that this... (answered by RAY100)

Hi. I need help with this LOG problem. I've figured out a) but I'm not sure what to do... (answered by josmiceli)

please help me solve this: If he population of a city doubles every 20 years, how long (answered by Alan3354)