Question

speed distance and time question number 8,9,10 ok
pls post photo​

Answer 1

1. Case 1

From A to B

Distance ⇒ 6 km

Speed ⇒ 12 km/h

Time ⇒ Distance ÷ Speed

⇒ 6 ÷ 12

⇒ 0.5 hours

Case 2

From B to A

Distance ⇒ 6 km

Speed ⇒ 10 km/h

Time ⇒ Distance ÷ Speed

⇒ 6 ÷ 10

⇒ 0.6 hours

Average Speed  ⇒ $\sf \dfrac{Distance \ Covered\ Totally }{Time \ Taken}$

⇒ $\sf \dfrac{6+6}{0.5+0.6}$

⇒ $\sf \dfrac{12}{1.1}$

Average = 10.90

∴ The average time taken is 10.90 km/h

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2. Time taken by the train to cover 160 km ⇒$\dfrac{160}{40} = 4 \ hours$

Time taken by the train to cover 180 km ⇒$\dfrac{180}{45} = 4 \ hours$

Time taken by the train to cover 200 km ⇒$\dfrac{200}{50} = 4 \ hours$

∴ Total time taken by the train was 4+4+4 = 12

(ii) Average Speed ⇒ $\dfrac{40+45+50}{3} = \dfrac{135}{3} = 45\ km/h$

∴ Average Speed is 45 km/h

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3. (i) Case 1

Distance covered by train ⇒ 390 km

Speed ⇒ 90 km/h

Time Taken ⇒ Distance ÷ Speed

Time Taken ⇒ 390 ÷ 90 = $\dfrac{13}{3}$

Case 2

Distance covered by train ⇒ 670-390 = 280km

Time left  to travel remaining ⇒$\dfrac{73}{12} -\dfrac{13}{3}$

⇒ $\dfrac{73}{12} -\dfrac{13\times 4 }{3\times 4 }$

⇒ $\dfrac{73}{12} -\dfrac{52}{12}$

⇒ $\dfrac{21}{12}$

⇒ $\dfrac{7}{4}$

Speed for the rest of the journey ⇒ $280\div \dfrac{7}{4}$

⇒ $280\times \dfrac{4}{7}$

⇒ $\dfrac{1960}{4}$

⇒ 160 km/h

∴ The train continued the journey at the speed of 160 km/h

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3. (ii) Total distance covered ⇒ 630 km

Time Taken ⇒ 9 hours

Case 1

Distance covered ⇒ $\dfrac{2}{3} \times 630 = 420\ km$

Speed ⇒  60 km/h

Time taken ⇒ Distance ÷ Speed

Time taken ⇒ 420 ÷ 60 = 7 hours

Case 2

Distance covered ⇒ 630-420 = 210 km

Time taken ⇒ 2 hours

Speed ⇒ Distance ÷ Time

Speed ⇒ 210 ÷ 2 = 105 km/h

∴ The speed for the rest of the journey was 105 km/h

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Answer 2

Answer:575 is your answer

Step-by-step explanation: