Question

If $18$ notebooks cost Rs. $333$, find the cost of $6$ notebooks?

Answer 1

Hint: Here we are given the cost of $18$ notebooks which is Rs. $333$. After that find the cost for $1$ notebook and then find the cost for $6$ notebooks.

Complete step-by-step answer:
Here we are given that, $18$ notebooks cost Rs. $333$.
So, cost for $18$ notebooks$=$ Rs. $333$
Now let us find the cost for a $1$ notebook.
cost for $1$ notebook$=$ Rs. ${\displaystyle \frac{333}{18}}$
Now simplifying we get,
cost for $1$ notebooks$=$ Rs. ${\displaystyle \frac{111}{6}}$
Now let us find the cost for $6$ notebooks.
So, cost for $6$ notebooks$=$ Rs. $({\displaystyle \frac{111}{6}}\times 6)$
Again, simplifying we get,
cost for $6$ notebooks$=$ Rs. $111$
Therefore, the cost for $6$ notebooks is Rs. $111$.

Additional information:
Direct Variation is said to be the relationship between two variables in which one is a constant multiple of the other. For example, when one variable changes the other, then they are said to be in proportion. Direct variation means when one quantity changes, the other quantity also changes in direct proportion. Inverse variation is exactly opposite to this. If the two values of the objects are related in such a way that an increase or decrease in the value of one object affects the value of the other, which is termed as a variation. Direct proportion or direct variation is the relation between two quantities where the ratio of the two is equal to a constant value.

Note: A relationship between two variables in which one is a constant multiple of the other. In particular, when one variable changes the other changes in proportion to the first. Direct Variation is said to be the relationship between two variables in which one is a constant multiple of the other.