Предмет: Алгебра, автор: tsklizkova

велосипедист ехал 2 часа по лесной дороге и 1 час по шоссе,всего он проехал 40 км,скорость его была на шоссе на 4 км/ч больше,чем на лесной,с какой скоростью он ехал по шоссе,а сколько по лесной

tsklizkova: спасибо большое!!!

Ответы

Автор ответа: 12345дика

14

Пусть х -скорость по шоссе, у - скорость по лесной дороге, тогдах = у + 4 (1)Длина лесной дорги 2·у, длина шоссе 1·х = х. Всего велосипедист проехал40км.х + 2у = 40 (2)Подставим (1) в (2)у + 4+ 2у = 403у = 36у = 12 - скорость на лесной дороге.Из (1):х = 12 + 4 = 16 - скорость на шоссе.Ответ: 16 км/ч - скорость на шоссе, 12км/ч - скорость на лесной дороге

Автор ответа: kowalewaeugeniy

12

2х + х + 4 = 40
3х = 40 - 4
3х = 36
х = 12 км/ч скорость велосипедиста на лесной дороге
12 + 4 = 16 км/ч скорость велосипедиста на шоссе

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