Предмет: Математика, автор: qeqeqeqw94

Дам 20 баллов решите 972 и ещё 971 и 973 Решите пожалуйста

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Ответы

Автор ответа: ildar502020

Ответ:

Пошаговое объяснение:

972. 75 км за 3 часа

S=vt. 75=3*v;

v=75/3 = 25 км/час

Осталось 250-75 = 175 км

За t=175/25 = 7 часов пройдет остаток (175 км) пути.

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971. 1200 м по течению за 10 минут

Скорость по течению v=s/t = 1200/10 = 120 м/мин.

Скорость против течения v=120-90 = 30 м/мин

1200 м против течения со скоростью 30 м/мин

За t=s/v = 1200/30 = 40 минут проплывет против течения.

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973. 200 грамм ------------- 3 р. 20 к = 320 копеек

1000 грамм ------------------------- x коп

200/1000 = 320/x;

x=1000*320/200;

x= 1600 копеек = 1600/100=16 рублей стоит 1 кг конфет

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