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,
(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.