Предмет: Математика, автор: margulank

На трёх полках стоят книги. На первой 1/4 всех книг, на второй полке 40% всех книг,
а на третьей полке 28 книг. Сколько книг стоят на трёх полках?

Ответы

Автор ответа: CVita

0

х-1/4х-0,4х=28
х-1/4х-4/10х=28
7/20х=28
х=80 книг - стоит на полках

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