A shop sells packets of biscuits for two pound 36 each. The packets of biscuits are currently on offer: buy one, get one half price. Roger has 27 pounds 50. He wants to buy as many packets of biscuits as possible. How many packets of biscuits can Roger buy?
We’re told in the question that one packet of biscuits cost two pound 36. The offer in the shop allows us to buy one and get one at half price. A half of two pound 36 is calculated by dividing 2.36 by two. This is equal to 1.18 or one pound and 18 pence.
We can, therefore, calculate the cost of buying two packets of biscuits by adding
2.36 to 1.18. This is equal to 3.54. Therefore, two packets of biscuits cost three pound and 54 pence. Roger has a total of 27 pounds and 50 pence. Our next step is to divide this by 3.54. 27.5 divided by 3.54 is equal to 7.768 and so on.
As we can only buy whole packs of biscuits, we need to round this down to seven. As two packets of biscuits cost three pounds and 54 pence, Roger can afford seven
times two packets. Multiplying seven by 3.54 gives us the total cost of 14 packets of biscuits. Seven multiplied by 3.54 is equal to 24.78. This means that 14 packets of biscuits will cost Roger 24 pounds and 78 pence.
As Roger had 27 pound 50, he still has some money left over. This means we can work out whether Roger can afford one more pack of biscuits at full
price. 15 packets of biscuits would cost 24 pound 78 plus 2 pound 36, the cost of one more
pack. This is equal to 27 pound and 14 pence.
As 27 pounds and 14 pence is less than 27 pounds and 50 pence, Roger can buy 15
packets of biscuits.