b) My friend wasn't waiting for me when I arrived late. 7.a) When did he have the accident? -As he was climbing up the ladder. b) When was he having the accident? -As he was climbing up the ladder. 8.a) l read a book when she sent me an SMS. b) l was reading a book when she sent me am SMS. 9.a) Did you eеat lunch when the fire alarm rang? b) Were you eating luncn when the fire alarm rang. 10.a) lt was a beautiful day The sun shone and there wasn't a cloud in the sky. b) lt was a beautiful day. The sun was shining and there wasn't a cloud in the sky.
Look at the of sentences below. Both of them are grammatically correct. Choose one sentence in each pair, a or b, that is more logical. 1.a) lt rained heavily when I ran for the bus. B) lt was raining heavily when I ran for the bus. 2.a) The rain jjust came into the station when we arrived on the platform. b) The train was just coming into the station when we arrived on the platform. 3.a) He broke his leg while riding his bike at the weekend. b) He was breaking his leg while riding his bike at the weekend. 4.a) While I was watching TV, someone knocked on the window. bjWhile I was watching TV, someone was knocked on the window. 5 a) No wonder she fell off her bike. She didnt Innk here che iwac in
6 Complete the sentences with when or while. 1) The boys were playing football ... the ball flew into the window. 2) Ronny was painting the fence ... the bucket of paint turned over. 3) Denny was putting a tent ... the girls were gathering wood for fire. 4) Rita was sleeping .. the alarm- rang. 5) Nelly was peeling potatоes her sister was cutting chicken into pieces. 6) Nigel was skiing he fell down and broke his leg. 7) They were arguing ... Mrs Elliot entered the room. 8) ... my mother was watching her favorite show on TV, father making coffee. 9) She was tying a letter some mistakes. 10) They were driving towards the village it started clock she found to snow.
Пусть t ч - время автобуса при старом расписании, тогда его средняя скорость составляла 325/t км/ч. 40 мин = 2/3 ч По новому расписанию время автобуса составляет (t- 2/3) ч, а средняя скорость равна 325/(t- 2/3) км/ч. По условию задачи, скорость движения по новому расписанию на 10 км/ч больше скорости автобуса по старому расписанию. Составим уравнение: 325/(t- 2/3) - 325/t =10 325/((3t-2)/3) -325/t =10 975/(3t-2) - 325/t = 10 |*t(3t-2) 975t - 975t + 650 = 10t(3t-2) 30t²-20t-650=0 3t²-2t-65=0 D=(-2)²-4*3*(-65)=784=28² t₁=(2+28)/6=5 t₂=(2-28)/6=-4.1/3<0 (лишний корень) t=5 ч - время автобуса по старому расписанию 325/5= 65 км/ч - скорость автобуса согласно старому расписанию 65+10=75 км/ч - скорость автобуса согласно новому расписанию ответ: 75 км/ч
b) My friend wasn't waiting for me when I arrived late. 7.a) When did he have the accident? -As he was climbing up the ladder. b) When was he having the accident? -As he was climbing up the ladder. 8.a) l read a book when she sent me an SMS. b) l was reading a book when she sent me am SMS. 9.a) Did you eеat lunch when the fire alarm rang? b) Were you eating luncn when the fire alarm rang. 10.a) lt was a beautiful day The sun shone and there wasn't a cloud in the sky. b) lt was a beautiful day. The sun was shining and there wasn't a cloud in the sky.
Look at the of sentences below. Both of them are grammatically correct. Choose one sentence in each pair, a or b, that is more logical. 1.a) lt rained heavily when I ran for the bus. B) lt was raining heavily when I ran for the bus. 2.a) The rain jjust came into the station when we arrived on the platform. b) The train was just coming into the station when we arrived on the platform. 3.a) He broke his leg while riding his bike at the weekend. b) He was breaking his leg while riding his bike at the weekend. 4.a) While I was watching TV, someone knocked on the window. bjWhile I was watching TV, someone was knocked on the window. 5 a) No wonder she fell off her bike. She didnt Innk here che iwac in
6 Complete the sentences with when or while. 1) The boys were playing football ... the ball flew into the window. 2) Ronny was painting the fence ... the bucket of paint turned over. 3) Denny was putting a tent ... the girls were gathering wood for fire. 4) Rita was sleeping .. the alarm- rang. 5) Nelly was peeling potatоes her sister was cutting chicken into pieces. 6) Nigel was skiing he fell down and broke his leg. 7) They were arguing ... Mrs Elliot entered the room. 8) ... my mother was watching her favorite show on TV, father making coffee. 9) She was tying a letter some mistakes. 10) They were driving towards the village it started clock she found to snow.
тогда его средняя скорость составляла 325/t км/ч.
40 мин = 2/3 ч
По новому расписанию время автобуса составляет (t- 2/3) ч,
а средняя скорость равна 325/(t- 2/3) км/ч.
По условию задачи, скорость движения по новому расписанию
на 10 км/ч больше скорости автобуса по старому расписанию.
Составим уравнение:
325/(t- 2/3) - 325/t =10
325/((3t-2)/3) -325/t =10
975/(3t-2) - 325/t = 10 |*t(3t-2)
975t - 975t + 650 = 10t(3t-2)
30t²-20t-650=0
3t²-2t-65=0
D=(-2)²-4*3*(-65)=784=28²
t₁=(2+28)/6=5
t₂=(2-28)/6=-4.1/3<0 (лишний корень)
t=5 ч - время автобуса по старому расписанию
325/5= 65 км/ч - скорость автобуса согласно старому расписанию
65+10=75 км/ч - скорость автобуса согласно новому расписанию
ответ: 75 км/ч