Question

# The cost of 1 litre of milk is Rs.7.50, then the cost of 30.5 litres of milk isA. Rs.22.75B. Rs.223.75C. Rs.228.75D. None of these

Hint: First of all, read the question carefully and then write the given data so that we can have a clear idea of what we have to find. Then multiply 30.5 litres of milk with cost to one litre of milk to get the cost of 30.5 litres of milk.

We know that if one article costs ${\text{Rs}}{\text{.}}x$, then $y$ articles costs ${\text{Rs}}{\text{.}}xy$.
So, cost of 30.5 litres of milk $= {\text{Rs}}{\text{.}}\left( {30.5 \times 7.50} \right) = {\text{Rs}}.228.75$
Note: Here we can check our answer by dividing the total cost of 30.5 litres by cost of one litre and the obtained values is equal to 30.5 then our answer is correct otherwise wrong. So, let us divide the cost of 30.5 litres with the cost of one litre i.e., $\dfrac{{228.75}}{{7.50}} = 30.5$. Since the obtained value is equal to 30.5 our answer is correct.