Definition: -The relation between two quantities (both of the same kind and in the same unit) obtained by dividing one quantity by the other, is called ratio.Therefore ration between two quantities x and y both of the same kind and in the same unit, is x / y and is often written as x: y (read as x to y or x is to y).
For example: -
i) The ration between 5 kg and 15 kg = 5 kg / 15 kg = 1 / 3 = 1 : 3
ii) The ratio between 800 gm. and 1.2 kg = 800 gm. / 1200 gm. = 2/3 =2:3
Question 1: The strength of a class is 50; out of which 30 are boys and rest are girls. Find the ratio between the number of boys and the number of girls in the class.
Solution: -Since, the strength of the class = 50
And, the number of boys in the class = 30
The number of girls in the class = 50 – 30
Therefore Required ratio = (No. of boys in the class) / (No. of girls in the class)
= 30 / 20
= 3 / 2
= 3: 2
Question 2: -A man’s monthly income is $1,500 out of which he spends $ 1, 250 every month. Find the ratio between his saving and expenditure.
Solution: - Since, the monthly income of the man =$ 1,500
And, his monthly expenditure = $ 1,250
His saving per month = $ 1,500 - $ 1,250 =$ 250