Comparing quantities with different units

The height of a tree is 13m and its picture in the book is 26cm long. Can we say that the height of the tree in the picture is twice that of the actual tree?

Obviously not, as we know actual tree is taller than the tree shown in the picture.

Height of the tree is 13m i.e. 1300 cm and the height of tree in the picture is just 26 cm.

Now the ratio between two heights 130026 = :

So we can say that the tree's actual height is 50 times than that of the picture in the book.

When we compare two quantities, they must be in the same units.

In general the ratio of two quantities a and b is written as a : b and we read it as a is to b.

The two quantities a and b are called terms of the ratio. First quantity 'a' is called first term or antecedent and second quantity 'b' is called second term or consequent.

1. Rafi has 16 red marbles and 4 blue marbles. Find the ratio of red marbles to blue marbles Rafi has?

Solution:

Red marbles : Blue marbles = 16 : 4 = :

Number of red marbles are 4 times than that of blue marbles.