mong các bạn mình Một xe máy đi từ thành phố Hà Tiên đến Rạch Giá. Trên quảng dường đàu từ Hà Tiên đến Kiên lương xe mấy đi với tốc độ 45km/giờ hết thời gian 40 phút. Sâu đó xe tiếp tục chuyển động trên quảng đường còn lại với tốc độ 50km/giờ biết thời gian là 90 phút A) Tính quảng đường từ Hà Tiên đến Kiên lương B) Tính tốc đọ trung bình của xe trên cả quảng dường từ hà tiên đến Rạch giá

2 câu trả lời

a, Đổi 40 phút = $\frac{2}{3}h$ ; 90 phút = 1,5h

Quãng đường từ Hà Tiên đến Kiên Lương là:

$S_1=v_1.t_1=45.\frac{2}{3}=30(km)$

b, Quãng đường còn lại xe đi là:

$S_2=v_2.t_2=50.1,5=75(km)$

Quãng đường từ Hà Tiên đến Rạch Giá là:

$S=S_1+S_2=30+75=105(km)$

Thời gian xe chuyển động trên cả quãng đường này là:

$t=t_1+t_2=\frac{2}{3}+1,5=\frac{13}{6}(h)$

Vận tốc trung bình của xe là:

$v_{tb}=\frac{S}{t}=\frac{105}{\frac{13}{6}}≈48,46(km/h)$

Vậy . . .

Quãng đường từ Hà Tiên đến Kiên Lương là:

`(45×40)÷60=30(km)`

Quãng đường từ Kiên Lương tới Rạch Giá là:

`(55×90)÷60=82,5(km)`

Tốc độ trung bình của xe trên cả quãng đường từ Hà Tiên đến Rạch Giá là:

`(30+82,5)÷2=56,25` (km/giờ)

Câu hỏi trong lớp Xem thêm

I. Circle the correct one. “Too or Enough” 1) This car is too/enough old. We cannot go anywhere. 2) This book is too/enough thick for me to read. 3) That dress is cheap too/enough to buy. 4) This question is too/enough complicated to answer. 5) Everybody is too/enough excited about the holiday to focus on their work. 6) I can join that club. I’m young too/enough. 7) She can’t come with us to the bar. She’s too/enough young. 8) We have too/enough eggs to make a cake. 9) Do we have too/enough time to catch the bus? 10)This boy is too/enough noisy. I can’t study! 11)Mary’s room is too/enough dirty. Her mom is angry. 12)Tom is tall too/enough to join a basketball team. 13)This bag is too/enough heavy. I can’t carry it. II. Complete with “too” or “enough”. 1- She is clever ........................ to pass the test. 2- The skirt is ........................ long for you. 3- Kate is .......................young to drive a car. 4- There is ......................... meat in the fridge for the whole week. 5- I didn’t work hard ........................ to pass the exam. 6- We can’t buy the car because it is .......................expensive. 7- He can’t sleep because he drinks .......................much coffee. 8- Are you tall ...................... to reach that shelf? 9- They often take the bus to school because it’s ................... far to walk. 10- She isn’t fast ...................... to win the race. 11- There’s .......................food for everyone to eat. 12- She isn’t speaking clearly ................for me to understand. III. Complete the sentences with “too – enough” by using the words given. 1) I don’t want to eat that soup. It is _______________________. ( cold ) 2) She can’t come to party with us. She isn’t _______________________. ( old ) 3) They need much money. That car is _______________________ to buy. ( expensive ) 4) We don’t need to worry about the food. It is _______________________. (fresh ) 5) I missed the bus because I got up _______________________. ( late ) 6) I cannot buy that dress. It isn’t _______________________ for me to buy. ( cheap ) 7) I cannot climb that mountain. It is _______________________. ( high ) 8) You should help your sister. She is _______________________ to eat herself. (young) 9) It is _______________________ to see the way. ( foggy ) 10) He is _______________________ to win the race. ( fast ) 11) He is _______________________ to be the headmaster. ( qualified ) 12) Don’t want any help from him. He is _____________________ to help anyone. (rude) 13) The movie was _______________________. I couldn’t watch it. ( boring ) 14) Ben is _______________________ to solve the problems. He never studies. ( lazy ) 15) The questions were _______________________ to solve. ( difficult ) 16) Jeremy is _______________________ to talk people. ( shy ) 17) Ashley is _______________________ to pass the test. ( hardworking ) 18) I can’t wear this t-shirt. It is _______________________. ( small ) Giúp mk vs, tuy ns dài nhưg rấc cần sự giúp đỡ! Mk cần 2 bn lm ạ, bn nào có sức thì làm 2 bài, còn bn còn lại lm 1 bài a

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