Andrei hated the culegere . Its thick, blue cover—creased at the spine, coffee-stained on the back—sat on his desk like a small, mute tyrant. His father had bought it in September with the best intentions: “Three problems every night, and you’ll be top of the class.”
He wrote the equations: let son = s , father = f . (f = 4s) (f + 18 = 2(s + 18) \Rightarrow 4s + 18 = 2s + 36 \Rightarrow 2s = 18 \Rightarrow s = 9, f = 36.) Sum = (9 + 36 = 45), which is not prime. A contradiction. culegere matematica clasa a 9 a
Andrei stared at the page. For the first time, the culegere wasn’t asking for a number. It was asking for a reason . He wrote in his notebook: Andrei hated the culegere
One rainy Thursday, he flipped to a random page. Problem 789: A father is three times as old as his son. In 12 years, he will be twice as old. Find their ages. (f = 4s) (f + 18 = 2(s