Question

The milk bill of a family is Rs.1200 for 30 days. What would be the milk bill of that family for 12 days?

Answer 1

Hint: The above question is based on the concept of basic mathematical operations. The main approach towards solving the equation is to calculate the cost of milk for 12 days where the cost of milk for 30 days is given and we have to first find cost of milk for 1 day and then multiply by 12 to get cost of milk for 12 days.

Complete step by step answer:
In the above given question, the milk bill of a family is given is Rs 1200 for 30 days.
So now further we will first need to calculate the cost of milk for one day so that we can further calculate it for 12 days.
So the cost of milk for 30 Days is Rs.1200. It can be written mathematically as,
Cost for 30 days$ = 1200$
Then to calculate for the cost of one day we divide 30 on both the sides of the equal to sign we get,
Cost for \[\dfrac{{30}}{{30}}\]days $ = \dfrac{{1200}}{{30}}$
Cost for 1 day=40.
Now we have been asked to calculate cost for 12 days, we have to multiply 12 on both the sides.
Cost for 12days= \[40 \times 12 = 480\]

Therefore, the milk bill of that family for 12 days is 480rupees.

Note: An important thing to note is that the above method which is used to solve is called the cross multiplication method. The number 1200 is in front of 30 and 12 is multiplied by it when 30 is brought in the denominator.