Homework Help Forum: 11th grade

Posted by jordan on Thursday, October 15, 2009 at 1:21pm.

Yesterday Lucy walked 2 hours and 1/2 jogged hour and covered 6.25 miles. Today she walked for 3 hours and jogged for 1 hour and covered 10.25 miles. Assuming a constant walking rate and a constant jogging rate, how fast did she walk and how fast did she jog? Define two variables, write a system of equations, and solve to find the walking rate and the jogging rate. Justify your answer by showing how you solved the problem. w- walking j- jogging 2w + .5j= 6.25 --> 3(2w+.5j)= 3(6.25) 3w + 1j= 10.25 --> -2(3w+1j)= -2(10.25 6w + 1.5j= 18.75 -6w - 2j= -20.50 ----------------- -.5j=-1.75 j=.3 2w + .5(.3)= 6.25 2w + 15= 6.25 2w= 6.10 w= 3.05 check: 2(3.05) + .5(.3)= 6.25 (correct) 3(3.05) + 1(.3)= 9.45(wrong!!) it should be 10.25.

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:22pm

  since when is 1.75/5 = .3?

  
  

• 11th grade - jordan, Thursday, October 15, 2009 at 1:26pm

  -.5/1.75= -.2857...or .3

  
  

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:28pm

  Lord, Jordan. you have a*x=b then x= b/a NOT a/b

  
  

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:29pm

  I get 1.75/.5=3.5 check that.

  
  

• 11th grade - jordan, Thursday, October 15, 2009 at 1:29pm

  wow haha im lost... 6w + 1.5j= 18.75 -6w - 2j= -20.50 ----------------- -.5j=-1.75 j=.3 ? why would i multiply?

  
  

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:30pm

  Jordan, this is pretty basic. .5 j= 1.75 divide both sides by .5 j= 1.75/.5

  
  

• 11th grade - jordan, Thursday, October 15, 2009 at 1:32pm

  But, if i did get 3.5 that would mess up getting 6.25 or 10.25. 2(3.05) + .5(.3)= 6.25--correct. 3(3.05) + 1(.3)= 9.45... this is the one where i went wrong. i went wrong.

  
  

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:36pm

  You have a lot of problems. YOu solved j as 3.5 so now solve for w, you first answer is WRONG. 2w + .5(3.5)= 6.25 solve for w.

  
  

• 11th grade - bobpursley, Thursday, October 15, 2009 at 1:37pm

  Jordan, if you are in ALG II, I recommend a tutor before you get lost.

  
  

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