1.DIRECT PROPORTION: Two Quantities are said to be directly proportional,
if on the increase (or decrease) of th one, the other increases(or decreases) 
to the same extent.

Ex:(i) Cost is directly proportional to the number of articles.(More articles,
       More cost).

  (ii)Work done is directly proportional to the number of men working on it.
      (More men, more work).

2.INDIRECT PROPORTION: Two Quantities are said to be indirectly 
proportional,if on the increase of the one , the other decreases to the same 
extent and vice-versa.

Ex:(i) The time taken by a car covering a certain distance is inversely 
       proportional to th speed of the car.(More speed, less is the time taken
       to cover the distance).

   (ii)Time taken to finish a work is inversely proportional to the number 
       of persons working at it.
       (More persons, less is the time taken to finish a job).

NOTE: In solving Questions by chain rule, we compare every item with the 
term to be found out. 



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