Предмет: Математика, автор: tanya1995tanya

В трех районах города 12 тыс жителей. Сколько жителей в каждом районе, если известно, что 2/3 числа жителей 1-го района составляют 0,5 числа жителей 2-го района и 2/5 числа жителей 3-го района? НУЖНО СОСТАВИТЬ УРАВНЕНИЕ С НЕИЗВЕСТНОЙ "Х" !!!

Ответы

Автор ответа: cpprik

Число жителей 1-го района - Х
Число жителей 2-го района 2/3·Х:0,5=4/3·Х
Число жителей 3-го района 2/3·Х:2/5=5/3·Х

Составим уравнение Х+4/3·Х+5/3·Х=1200
Х+9/3·Х=12000 ⇒ 4Х=1200 ⇒ Х=300
Далее находим число жителей 2-го и 3-го районов.

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