Examples of Chain Rule 1
In this class, we discuss Examples of Chain Rule 1.
The reader should have prior knowledge of proportions and ratios. Click Here.
Directly Proportional: Two quantities are directly proportional. If the increase of one quantity then the other quantity increase to the same extent.
Example: Cost is directly proportional to the number of articles.
More articles cost more.
Indirectly Proportional: If one of the quantities increases, the other quantity decreases to the same extent.
Example: more speed, less time taken
Example 1:
If fifteen toys cost Rs 234, what do 35 toys cost?
Solution:
More toys more cost – Directly proportional
15: 35:: 234: x
Product of extremes = product of mean terms from proportions formulae
15 * x = 35 * 234
x = 546
Example 2:
If 36 men can do a piece of work in 25 hours, how many hours will fifteen men do it?
Solution:
Fewer men more hours – Indirectly proportional
Important to remember: We reverse the ratios for indirectly proportional
36: 15 written as 15: 36
15: 36:: 25: x
Product of extremes = product of mean terms
15x = 36* 25
x = 60
= 60 hours