Question

the price of a dozen notebooks is ¥144. Find the cost of 20 notebooks​

Answer 1

Cost of 12 Books = 144 ¥
Hence, Cost of One book = (144/12) ¥ = 12 ¥
$\therefore$ Cost of 20 Notebooks = 20×12 =240 ¥

Answer 2

when you are given price of a material and asked to find cost x number multiply the cost with the number given in the question so answer is 144*20.If it is askes in the converse way divide the numbers.So 144/12.and multiply the answer with 20.Answer is 144/12=12.then, 12*20 which is =240.