2)308
Пошаговое объяснение:
︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎
стала - 45км\ч
уменьшилась на 12 км\ч
1)12+45 = 57 ( км\ч) - начальная скорость
ответ : 57 км\ч