Question

A bike travels 30 km at a uniform speed of 50 km/hr and next 30 km at uniform speed of 40 km/hr.find average speed

Answer 1

Hope u like my process
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Formula to be used :
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Time taken (t) = distance /speed
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For first 30 km,

Time taken (t 1) =30/50 = 3/5 hr

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
For next 30 km,

Time taken (t 2) = 30/40 = ¾ hr

So average speed = total distance /total time
$= \frac{30 + 30}{ \frac{3}{5} + \frac{3}{4} } \\ = \frac{60}{ \frac{12 + 15}{20} } = \frac{60 \times 20}{27} = \frac{400}{9} \\ = 44.44 \: km \: {hr}^{ - 1}$
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Answer 2

Answer :

• The average speed of the bike = 44.4 km h¯¹

Given :

• A bike travels 30 km at a uniform speed of 50 km /h¯¹

• Next 30 km at uniform speed of 40 km/h ¯¹

To find :

• The average speed of the bike = ?

Step-by-step explanation :

In the first part, the bike travels a distance of 30 km at a speed of 50 km per hour.

Given,

Speed = 50 km h ¯¹

Distance = 30 km

Time = ?

Speed = Distance travelled / Time taken

∴ Time = Distance /Speed

Time, t₁ = 30/50 hours

= 3/5 hours

For the second part , the bike travels a distance of 30 km at a speed of 40 km h¯¹,

Given,

Speed = 40 km h ¯¹

Distance = 30 km

Time = ?

Time, t₂ = 30/40

= 3/4 hours

We cn get the total time taken by the bike for the whole journey by adding the above two values t₁ and t₂ , we get

Total time taken = 3/4 + 3/4

= 12+15/20

= 27/20 hours

Total distance travelled = 30 + 30

= 60 km

Average Speed = Total distance traveled/Total time taken

Substituting the values in above formula, we get

= 60 × 20 / 27

= 1200/27

= 44.4

Thus, the average speed of the bike = 44. 4 km h ¯¹.