Предмет: Алгебра, автор: stolyarovsolomon0

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Водно-сольовий розчин містив 3 кг солі, концентрація якої
була менша від 20 %. До цього розчину додали 6 кг солі, після
чого концентрація солі збільшилася на 15 %. Якою була почат�
кова маса розчину?

Ответы

Автор ответа: katetok89

2

кількість розчину у початковому розчині, що не є сіллю, становить (1-0.2)x = 0.8x кг.

Після додавання 6 кг солі, загальна маса розчину стала x + 6 кг, а кількість солі в розчині стала 3 + 6 = 9 кг. Концентрація солі тепер становить 15% більше, ніж в початковому розчині, тобто 0.15 + 0.2 = 0.35.

3 кг + 6 кг = 9 кг

0.8x + 6 кг = 0.35(x + 6 кг)

0.8x + 6 кг = 0.35x + 2.1 кг

0.45x = 3.9 кг

x = 8.67 кг

Відповідь: початкова маса розчину дорівнювала 8.67 кг.

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