Предмет: Математика, автор: v1perr

В школьном тесте 5 разделов, каждый из которых содержит одинаковое количество вопросов. Антон правильно ответил на 20 вопросов. При этом процент его верных ответов оказался больше 60, но меньше 70. Сколько всего вопросов было в тесте?

Ответы

Автор ответа: Arailyevil

Ответ:

Пошаговое объяснение:

Пусть в каждом разделе было x вопросов. Тогда всего было 5х вопросов. Если Антон решил 20 вопросов, то процент правильно решенных вопросов равен 20/5x = 4/x. Знаем, что 0.6 < 4/x < 0.7, нужно найти такое целое число х, что выполняется данное двойное неравенство. Такой х равен 6 (4/6 = 0.(6), 0.6 < 0.(6) < 0.7). Значит всего в тесте было 6*5 = 30 вопросов.

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