SOLUTION: Question 1: Sarah takes 6 hours to complete a job which mary could do in half the time. how many hours would it take to complete the job if they both worked together? Question 2

Question 294082: Question 1: Sarah takes 6 hours to complete a job which mary could do in half the time. how many hours would it take to complete the job if they both worked together?
Question 2: The time it takes to empty a tank varies inversely as the rate of pumping. if a pump working at 600 kl/min takes 45 minutes to empty a tank. how long would it take to empty the same tank if the rate was increased to 1000 kl/min?
Any help will be greatly appreciated. thx you very much in advance.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Question 1: Sarah takes 6 hours to complete a job which mary could do in half the time.
how many hours would it take to complete the job if they both worked together?
:
From the given information we know Mary takes 3 hrs to complete the job
:
Let t = time required when they work together
:
Let the competed job = 1
:
+ = 1
Multiply by 6, results:
t + 2t = 6
3t = 6
t = 2 hrs working together
:
:
Question 2: The time it takes to empty a tank varies inversely as the rate of pumping.
if a pump working at 600 kl/min takes 45 minutes to empty a tank.
how long would it take to empty the same tank if the rate was increased to 1000 kl/min?
:
Let x = time required when pumping 1000kl/min
:
An inverse ratio equation
=
Cross multiply
1000x = 600 * 45
x =
x = 27 min when it pumps at 1000kl/min