Question

144. A car completes a certain journey in 11 hours.
It covers first half of the distance at the speed
of 50 kmph and the rest half at the speed of 60
kmph. The total distance of the journey is :
(a) 605 km (b) 300 km (c) 500 km (d) 600 km​

Answer 1

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✤ Required Answer:

✒ GiveN:

• Total time taken = 11 hours
• First half distance with speed = 50 km/hr
• Second half distance with speed = 60 km/hr

✒ To FinD:

• Total distance travelled by the car?

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✤ How to solve?

Here, we have to apply the distance, time and speed relation to get the solution. The relation is:

$\large{ \boxed{ \rm{Speed = \frac{Distance}{Time \: taken} }}}$

We are given with the total time, and we can assume the distance as any variable. Speed is also given. So, we can find the solution.

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✤ Solution:

Let,

• Distance travelled by the body = d

In the first half,

• Distance = d/2
• Speed = 50 km/hr

By using formula,

⇛ Speed = Distance/Time

⇛ 50 km/hr = d/2 / Time

⇛ Time = d/2 km / 50 km/hr

⇛ Time = d/100 hr

In the second half,

• Distance = d/2
• Speed = 60 km/hr

By using formula,

⇛ Speed = Distance/Time

⇛ 60 km/hr = d/2 / Time

⇛ Time = d/2 km / 60 km/hr

⇛ Time = d/120 hr

We have, ATQ

• Total time taken = 11 hrs

⇛ So, d/100 + d/120 hrs = 11 hrs

⇛ 6d + 5d /600 = 11 hrs

⇛ 11d / 600 = 11 hrs

⇛ d = 600 × 11 / 11 km

⇛ d = 600 km

☸ Therefore, Correct option is D

⚘ Hence, solved !!

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