The ratio of the number of blue balls to the number of red balls is one to three.

• The ratio 1 to 3 is written as 1:3.   
• The ratio of the number of red balls to the number of blue balls is three to one as is written as 3:1.
• The ratio of the number of blue balls to all the balls is 1:4.
• The ratio of all the balls to the number of red balls is 4:3.

Puan Sameen buys some ribbons to decorate a few wedding gifts.
The length of the pink ribbon and the green ribbon is 7 m and 3 m respectively.

• The ratio of the length of the pink ribbon to the green ribbon is 7:3.
• The ratio of the length of the green ribbon to the pink ribbon is 3:7.
• The ratio of length of the pink ribbon to the total length ribbons is 7:10. We can write 7:10 as \(\dfrac{7}{10}\).
• The ratio of the total length of the ribbons to the green ribbon is 10:3 or \(\dfrac{10}{3}\).