Question

A car cover a distance in 40 minutes with an average speed of 75 km hour . what should be the average speed to cover distance in four minutes​

Answer 1

Answer :

$\underline{\boxed{\sf{Average\:Speed\:=\:750\:km/hr}}}$

Step-by-step Explanation :

Let the distance be x km.

Given that, a car cover a distance in 40 minutes with an average speed of 75 km/hr.

Time = 40 min and average speed = 75 km/hr

Now, convert min into hour. To convert min into hour divide with 60.

$\Rightarrow\:\sf{\frac{40}{60}\:=\:0.7\:hr}$

We know that,

Distance = Speed × time

$\implies\:\sf{75\:\times\:0.7}$

$\implies\:\sf{52.5\:km}$

We have to find the average speed to cover distance in four minutes.

Distance = 52.5 km and time = 4 min

$\Rightarrow\:\sf{\frac{4}{60}\:=\:0.07\:hr}$

Speed = Distance/time

$\implies\:\sf{\dfrac{52.5}{0.07}}$

$\implies\:\sf{750\:km/hr}$

•°• 750 km/hr is the average speed to cover the distance in 4 min.

Answer 2

Question :--- A car cover a distance in 40 minutes with an average speed of 75 km per hour . what should be the average speed to cover same distance in four minutes ?

Formula used :---

→ Distance = Speed * Time ( where Speed and Time both have same Units ).

→ Speed = Distance/Time.

→ 1 hour = 60 minutes .

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Solution :----

Car Speed Given = 75km/h .

→ Time to cover distance = 40 minutes = (40/60) = (2/3) Hours .

So, Distance Car will cover will be = S * T

→ D = 75 * (2/3)

→ D = 50km

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Now, we have to Find Speed of car, if the car will cover same Distance in 4 minutes ?

So,

→ Distance to cover = 50km.

→ Time = 4 minutes = (4/60) = (1/15) Hours.

So,

→ Speed = (Distance / Time.)

Putting values we get,

→ Speed = 50/(1/15)

→ Speed = 50 * (15/1)

→ Speed = 750km/h .

Hence, Average Speed of Car will be 750km/h to cover The same Distance in 4 minutes.

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Solution (2) :---

★★ Shortcut Trick.★★

❂❂ When the distance is constant, then speed is inversely proportional to time. ❂❂

So,

☛ (S1/S2) = (T2/T1)

Given ,

S1 = 75km/h

T1 = 40 min. = (2/3) hours .

T2 = 4 min . = (1/15) Hours.

Putting Values we get,

➥ (75/S2) = (2/3)/(1/15)

➥ (75/S2) = (2/3) * (15/1)

➥ (75/S2) = 10

➥ S2 = 75 * 10

➥ S2 = 750km/h .

Hence, Speed at Second Time will be 750km/h.