Question

Sumit bought 2 notebooks (each costing Rs.16.5), 5 pencils (each costing Rs. 2.5) and a pencil box for Rs.36.75. He gave a 100 rupee note to the shopkeeper. What amount would the shopkeeper return him? \[\]

Answer 1

Hint: We find the cost of 2 notebooks by multiplying 2 to the cost of one notebook. We find the cost of 5 pencils by multiplying 2 to the cost of one pencil. We add the costs of 2 notebooks, 5 pencils and 1 pencil box to get know the total cost Sumit has to pay to the shopkeeper. We subtract the total cost from 100 rupees to know the amount the shopkeeper will return to Sumit. \[\]

Complete step by step answer:
We are given in the question that Sumit bought 2 notebooks and the cost of each note book is 16.5 rupees. The word each man's one and hence the price of one note book is 16.5 rupees. So the price of two notebooks is two times the price of one note book which is $2\times 16.5=33.0$ rupees.\[\]
 We are further given the question that he has 5 pencils and the cost each pencil is 2.5 rupees. So the price of 5 pencils is 5 times the price of one pencil which is $5\times 2.5=12.5$ rupees. \[\]
We are further given the question that he also bought a pencil box of 36.75 rupees and 100 rupee note to the shopkeeper. \[\]
The total of amount of rupees Sumit gave to the shopkeeper is the sum of cost of 2 notebooks, 5 pencils and the pencil box which is $33.0+12.5+36.75=82.25$ rupees.\[\]

So the shopkeeper will return all the extra money after taking 82.25 rupees. So he will return $100-82.25=17.75$ rupees of Sumit. \[\]

Note: We note to always give the decimal point in the product at $n$ places from the right where $n$ is the total number of digits after the decimal points of the numbers we are multiplying. When we are adding decimals we must remember to add the fractional part after the decimal first. Similarly we should do for subtraction as addition of decimals.