Skip Navigation Links
   
Algebra I: Quadratic Problem on Time and Work
To enroll in any of our courses, click here
 
   
Quadratic Problem on Time and Work

Example: A takes 6 days less than the time taken by B to finish a piece of work. If both A and B together can finish it in 4 days, find the time taken by B to finish the work.
People who saw this lesson also found the
following lessons useful:
Spherical Shell
Linear Equation: Miscellaneous Problem
Right Circular Hollow Cylinder
Relationship between H.C.F. and L.C.M.
Solving Trigonometric Equations
Solution: Assume B alone takes x days to finish the work. Then, A alone can finish it in (x - 6) days.
Now,
(A's one day's work) + (B's one days's work) = 1/x + 1/(x - 6)
and,
(A + B)'s one day's work = 1/4.
Therefore,
    1/x + 1/(x - 6) = 1/4
(x - 6 + x)/[x (x - 6)] = 1/ 4
(2x - 6)/(x2 - 6x) = 1/4
8x - 24 = x2 - 6x
x2 - 14x + 24 = 0
x2 - 12x - 2x + 24 = 0
(x -12) (x - 2) = 0
x = 12 or x = 2.
But x cannot be less than 6. So, x = 12.
Hence, B alone can finish the work in 12 days.
 
   
As many of you know, Winpossible's online courses use a unique teaching method where an instructor explains the concepts in any given area to you in his/her own voice and handwriting, just like you see your teacher explain things to you on a blackboard in your classroom. All our courses include teacher's instruction, practice questions as well as end-of-lesson quizzes for practice. You can enroll in any of our online courses by clicking here.

The format of Winpossible's online courses is also very suitable for teachers who are using an interactive whiteboard such as Smartboard on Promethean in their classrooms, because the course lessons can be easily displayed on such interactive whiteboards. Volume pricing is available for schools interested in our online courses. For more information, please contact us at educators@winpossible.com.

 
       
     
 Copyright © Winpossible, 2010 - 2011
Best viewed in 1024x768 & IE 5.0 or later version