Человек проехал первую половину времени всег движения на автомобиле со скоростью 100км/ч,а вторую половину времени на велосипеде со скоростью 20км/ч. какова средняя скорость движения на всём пути?
s=v*t
пусть t -всё затраченное время.
тогда весь пройденный путь составил 100t/2 + 20t/2
v ср.= (100t/2 + 20t/2)/t=120t/2t=60 (км/ч)
ответ: средняя скорость на всём пути 60 км/ч.
так как время одинаково при движении на автомобиле и на велосипеде, то в данном случае можно сосчитать проще:
v ср.=(100+20)/2=60 (км/ч)
1)
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2. if you give me your address. i shall write you a letter.
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2)
1) this letter was received after his depature.
2) have you ever been attacked by dogs?
3) honey is gathered from flowers by bees.
4) the ship was driven against the rock by the storm.
5) the book was published by him last year.
6) these clothes are used by us only on special occasions.
