Вопрос школьника по предмету Математика
От двух пристаней одновременно отправились навстречу друг другу два теплохода. Первый имеет собственную скорость 24,5 км/ч и плывет по течению реки. Собственная скорость второго 28,5 км/ч. Скорость течения реки 2,5 км/ч. Через сколько часов теплоходы встретятся, если расстояние между пристанями равно 185,5 км?
Ответ учителя по предмету Математика
24.5+2.5=27 кмч скорость катера по течению 28.5-2.5=26 кмч скорость катера против течения 26+27=53 кмч скорость сближения катеров 185.5:53=3.5 или 3ч 30 мин
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Упражнения 1.Раскройте скобки, употребляя гла¬голы в Present или Past Simple.
I (to go) to bed at ten o’clock every day. 2. I (to go) to bed at ten o’clock yesterday. 3. My brother (to wash) his face every morning. 4. Yesterday he (to wash) his face at a quarter past seven. 5. I (not to have) history lessons every day. 6. We (not to rest) yesterday. 7. My brother (not to drink) cof¬fee yesterday. 8. My mother always (to take) a bus to get to work, but yesterday she (not to take) a bus. Yesterday she (to walk) to her office. 9. You (to talk) to the members of your family every day? — Yes, I …. But yesterday I (not to talk) to them: I (to be) very busy yesterday. 10. You (to come) home at six o’clock yesterday? — — No, I …. Yes¬terday I (to come) home from school at half past eight. I (to be) very tired. I (to have) dinner with my family. After dinner I (to be) very thirsty. I (to drink) two cups of tea. Then I (to rest). 11. Your sister (to go) to school every day? — — Yes, she ….
x-2/15=4/15+9/15
y+9/15=4/15+11/15
15/15-c9/19-6/19