Question

A car travelling at 72 km/h covers a certain distance
in 6 hours.
what should be the decrease in speed , If the same distance is to be covered in 8 hours ​

Answer 1

Answer:

given :-

A car with speed 60km/hr covers some distance in 8hrs.

The distance covered = (velocity) × (time)

                                     =60×8

                                     =480km

Given :-

That it has to cover the same distance in 7  

2

1

​  

hrs.  

So,velocity required =  

time

distance                                  

=15

480×2

​ =64km/hr

Step-by-step explanation:

Answer 2

Answer:

$\bigstar{\bold{Decrease\:in\:speed=18\:km/hr}}$

Step-by-step explanation:

$\Large{\underline{\bf{Given:}}}$

• Speed of the car = 72 km/hr
• Time taken = 6 hours

$\Large{\underline{\bf{To\:Find:}}}$

• Decrease in speed if the distance is to be covered in 8 hours

$\Large{\underline{\bf{Concept:}}}$

First find the distance travelled by the car using the formula. Next find the speed of the car in the second case. Subtracting the speed in second case from the speed in first case we get the value of speed decreased.

$\Large{\underline{\bf{Solution:}}}$

➙ Here we have to find the decrease in speed of the car.

➙ First we have to find the distance travelled by the car.

➙ We know that,

    Distance = Speed × Time

➙ Substituting the data,

    Distance = 72 × 6

    Distance = 432 km

➙ Hence the distance travelled by the car is 432 km.

➙ Now finding the speed of the car if time taken was 8 hours.

➙ We know that ,

    Speed = Distance/Time

➙ Substitute the data,

    Speed = 432/8

   Speed  = 54 km/hr

➙ Hence the speed of the car would be 54 km/hr if time taken was 8 hours.

➙ Now decrease in speed is given by,

   Decrease in speed = Speed in first case - Speed in second case

➙ Substituting the data,

    Decrease in speed = 72 - 54

    Decrease in speed = 18 km/hr

➙ Hence the decrease in speed is 18 km/hr.

 

    $\boxed{\bold{Decrease\:in\:speed=18\:km/hr}}$