Question

A vendor supplies 32 litres of milk in the morning and 68 litres of milk in the evening. If the milk costs Rs. 45 per litre, how much money is due to the vendor per day.

Answer 1

Hint: We will use the unitary method to find the total amount due to the vendor per day. We will first add the litres of milk supplied by the vendor in the morning and in the evening, that is (32 + 68) litres. Now, as the vendor charges Rs. 42 per litre of milk, we can find the cost of (32 + 68) litres milk, which will be the product of the cost of 1 litre milk and that of the total amount of milk supplied.

Complete step-by-step answer:
It is given in the question that a vendor supplies 32 litres of milk in the morning and 68 litres of milk in the evening. Now, the cost of milk per litre is Rs. 45 and we have been asked to find the amount of money due to the vendor per day. We will use the unitary method to find the total amount due to the vendor per day. As we know, the unitary method is a mathematical approach in which we find the cost of 1 unit first and then multiply it with the total number of required units.
Now, it is given that the vendor supplies 32 litres of milk in the morning and 68 litres of milk in the evening. So, the total quantity of milk supplied by the vendor per day = (milk supplied in the morning) + (milk supplied in the evening). So, we can say, (32 + 68) litres = 100 litres.
We know that the cost of 1 litre milk is given as Rs. 45. So,
The cost of 100 litres of milk will be = Rs. $\left( 45\times 100 \right)$ = Rs. 4,500.
Therefore, the amount due to the vendor per day would be Rs. 4,500.

Note: Many students multiply the quantity of milk in the morning by the quantity in the evening, that is, $\left( 32\times 68 \right)$ and as a result, they may get the due amount per day as, $\left( 32\times 68\times 45 \right)$, which is Rs. 97,920, which is a totally incorrect value. So, in order to get the correct value, we should find the sum of the total litres of the milk instead of finding its product. Thus, it is recommended that the students should do the calculations carefully to avoid mistakes.