Ratio Symbol

 
A relationship existing between the two quantities are termed as ratio and represented by a ratio symbol. The symbol used for ratio is ‘:’. A fraction symbol ‘/’ also represents a ratio.
For example, the ratio between the quantities ‘a’ and ‘b’ are written by using ratio symbol as,
a : b or a/b.Example Problems for Ratio Symbol:

 

 

Example: 1
A book shop has 50 Tamil books, 45 English books and 60 maths books.
a) What is the ratio of Tamil books to total number of books in a shop?
b) What is the ratio of maths books to English books?
Solution:
Given,
Number of Tamil books = 50
Number of English books = 45
Number of maths books = 60
Total number of books in a shop = Tamil books + English books + Maths books
= 50 + 45 + 60
= 155
a)
A ratio of Tamil books to total number of books is,
Tamil books : Total number of books
50 : 155
This ratio is also written as a ratio symbol ‘/’ as
`50/155` = `10/31`
The ratio of Tamil books to total books of a shop is 10:31.
b)
Ratio between maths books to English books is written using a ratio symbol as,
Number of maths books : Number of English books
60 : 45 = `60/45`
= `12/9`
= `4/3`
The ratio of maths books to English books is 4 : 3.
Example: 2
Sham age is 25 and Ram age is 2 times of Sham. Find the ratio of Sham’s age to Ram age.
Solution:
Sham’s age = 25
Ram’s age = 2 x Sham age
=2 x = 25
= 50
The relationship between Sham and Ram should be written using ratio symbol as,
25 : 50

or
`25/50` = `1/2`
The ratio of  Sham and Ram age is 1:2Practice Problems to Ratio Symbol:
Problem: 1
Find the equivalent ratio of 5:10?
Answer: 1:2

  

Problem: 2
A bag has 30 red balls and 40 white balls. Find out the ratio of red balls to white balls in a bag?
Answer: 3:4