Предмет: Алгебра, автор: bogomazsofiya

пожалуйста помогите!!!!
скласти системою рівнянь
2) За 3 год за течією і 4 год проти течії теплохід долає 380 км. За 1 год за течією та не 30 хв проти течії теплохід долае 85 км. Відшукайте власну швидкість теплохода та швидкість течії​

Ответы

Автор ответа: Пеппер
2

Ответ:

55 км/год;  5 км/год.

Объяснение:

Нехай власна швидкість теплохода х км/год, швидкість течії у км/год тоді за умовою:

3(х+у)+4(х-у)=380

х+у+0,5(х-у)=85

3х+3у+4х-4у=380

х+у+0,5х-0,5у=85

7х-у=380

1,5х+0,5у=85

у=7х-380

1,5х+0,5(7х-380)=85

у=7х-380

1,5х+3,5х-190=85

у=7х-380

5х=275

х=55

у=55*7-380=5

Власна швидкість теплохода 55 км/год, швидкість течії 5 км/год.

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