Question

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7. The distance between two places is 120 km. A car travelling at a certain speed can cover
the distance in 2 hours 30 minutes. By how many km/h should the speed of the car be
increased for it to take 30 minutes less to cover the distance?
7 th one

Answer 1

Question:-

The distance between two places is 120 km. A car travelling at a certain speed can cover the distance in 2 hours 30 minutes. By how many km/h should the speed of the car be increased for it to take 30 minutes less to cover the distance?

Answer:-

Given:

Distance between two places = 120 km

Time taken by the car = 2 hours 30 min

• 1 hr = 60 min

⟶ Time taken by the car = 2* 60 + 30

⟶ Time taken by the car = 150 min

• 1 min = 1/60 hrs

⟶ Time taken by the car = 150/60 hrs

⟶ Time taken by the car = 5/2 hrs

We know that,

Speed = Distance/time

⟶ Speed of the car = 120/(5/2)

⟶ Speed of the car = 120 * 2/5

⟶ Speed of the car = 48 km/hr

Now,

we have to find the increase in the speed if time taken by the car is 30 min less.

⟶ Time taken by the car (due to increase in the speed) = 2 hours 30 min - 30 min = 2 hrs.

So,

⟶ New Speed of the car = 120/2

⟶ New Speed of the car = 60 km/h

Now,

Difference between the original speed and the new speed of the car = (60 - 48) km/h = 12 km/h.

Therefore, the speed of the car should be increased by 12 km/h.

Answer 2

$\bf \huge{ \underline{ \underline{ \red{Question : }}}}$

The distance between two places is 120 km. A car travelling at a certain speed can cover the distance in 2 hours 30 minutes. By how many km/h should the speed of the car be increased for it to take 30 minutes less to cover the distance?

$\bf \huge{ \underline{ \underline{ \red{Answer:}}}}$

Given:

• The distance between two places is 120 km.

To find:

• Increased in speed

Explanation:

Distance = 120 km

$\star {\fbox{ \tt{ \: \: Speed \: = \: \frac{ Distance }{ Time \: \: } }}}$

Speed = 120 / 2.5

Speed = 48 km / hr

New Speed :-

=> 120 / 2

=> 60 km / hr

Increased in speed :

= > (60-48) km / hr

=> 12 km / hr

•°• Increased in speed is 12 km / hr...

Need to know :

• Speed = Distance / Time

• Distance = Speed * Time

• Time = Distance / Speed