Question

6. A man completes 30 km of a journey at 6 km/h and the
remaining 40 km of the journey in 5 h. Find the average speed for
the whole journey.
a.7 km/h b.8km/h
c.9km/h d. 10km/h​

Answer 1

Answer:

A man completes 30 km of a journey at 6 km/h and the remaining 40 km of the journey in 5 h. Find the average speed for the whole journey.

A) 6411 km / h

B) 7 km / h

C) 712 km / h

D) 8 km / h

um , correct answer is: option b) 7 km/h.

step by step explanation:

Total distance = 30 + 40 = 70 km

Total time taken = 306 + 5 = 606 = 10h

Therefore, Required average speed = 7010 = 7 km / h.

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Answer 2

FINAL ANSWER:-

$Average \: speed=7km/hr$

a. 7 km/h

GIVEN:-

• A man completes 30 km of a journey at 6 km/h

• The remaining 40 km of the journey in 5 h

TO FIND:-

the average speed for the whole journey

FORMULAS USED:-

• $Speed=\frac{distance}{time}$

• $Average \: speed=\frac{total\:distance\:covered}{total\:time\:taken}$

SOLUTION:-

Here,  

$S1= 6 km/h\:\:\:\: ;\:\:\: D1= 30 km\:\:\: ;\:\:\: T1=?\\D2=40 km\:\:\: ;\:\:\: T2=5 hr.$

As we have D1 , D2 , T2 to find average speed , but T1 is missing  

So by using $Speed=\frac{distance}{time}$ we have to find T1  

$S1=\frac{D1} {T1}\\6=\frac{30}{T1}\\T1=\frac{30}{6}\\T1= 5 hr.$

∴ Total distance = $D1 + D2$ ⇒$30+40$ ⇒ $70$

∴ Total time taken = $T1 + T2$ ⇒ $5+5$ ⇒ $10$

So now let’s find average speed as we have got total distance covered (70 km.) and total time taken (10 hr.)

$Average \: speed=\frac{total\:distance\:covered}{total\:time\:taken}\\Average \: speed=\frac{70}{10}$

$Average \: speed=7km/hr$

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