My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum


Reply
 
LinkBack Thread Tools Display Modes
October 19th, 2015, 02:21 PM   #1
Senior Member
 
Joined: Jan 2015
From: London

Posts: 108
Thanks: 2

Proportionality Hard Worded Question

The pressure on a diver under water is directly proportional to the square of her depth below the surface of the water. The diver has reached a depth of 10 metres. How much further must she descend for the pressure to double?
jamesbrown is offline  
 
October 19th, 2015, 03:07 PM   #2
Math Team
 
Joined: Jul 2011
From: Texas

Posts: 2,887
Thanks: 1506

Quote:
The pressure on a diver under water is directly proportional to the square of her depth below the surface of the water.
$P = k \cdot d^2$, where $k$ is the constant of proportionality

$2P = 2k \cdot d^2$

$2P = k \cdot 2d^2$

$2P = k \cdot (\sqrt{2} \cdot d)^2$
skeeter is offline  
October 20th, 2015, 07:55 AM   #3
Senior Member
 
Joined: Jan 2015
From: London

Posts: 108
Thanks: 2

Could you please expand on your answer so that we actually know how much further she has gone before the pressure doubles
jamesbrown is offline  
October 20th, 2015, 02:16 PM   #4
Math Team
 
Joined: Jul 2011
From: Texas

Posts: 2,887
Thanks: 1506

Quote:
Originally Posted by jamesbrown View Post
Could you please expand on your answer so that we actually know how much further she has gone before the pressure doubles
final depth - initial depth ...

$\sqrt{2} \cdot d - d = d(\sqrt{2}-1)$

now substitute the given value for the initial depth into the expression.
skeeter is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
hard, proportionality, question, worded



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Proportionality statement musicboy Algebra 2 May 18th, 2014 06:58 AM
Simple proportionality question sumitdeole Algebra 1 June 11th, 2013 09:00 AM
Worded infinite series problem Dragonkiller Real Analysis 1 August 7th, 2012 12:25 PM
Proportionality stuvalt309 Algebra 4 January 23rd, 2011 12:26 AM
Proportionality constant Problem Darpa.Chief Algebra 4 April 27th, 2010 10:50 AM





Copyright © 2019 My Math Forum. All rights reserved.