Question

A car with speed 60 km/hr takes 8 hours to travel some distance. What should be the increase in the speed if the same distance is to be covered in 7 /1 2 hours?

Answer 1

Answer:

4 km/h more

Step-by-step explanation:

Total distance taken by car = speed x time = 60 X 8 = 480

speed of it if it takes 7.5 hours = distance / time = 480 / 7.5 = 64

64-60= 4 kmph

Answer 2

Given :-

Speed of the car = 60 km/hr

Time taken by the car = 8 hours

To Find :-

The increase in the speed if the same distance is to be covered in 7 /1 2 hours.

Analysis :-

First find the distance by substituting their values in the respective formula.

Then find the speed by substituting their values in the respective formula.

Finally in order to find the increase in speed, subtract the original speed from the increased speed.

Solution :-

We know that,

• s = Speed
• t = Time
• d = Distance

By the formula,

$\underline{\boxed{\sf Total \ distance=Speed \times Time}}$

Given that,

Speed (s) = 60 km/hr

Time (t) = 8 hours

Substituting their values,

Distance = 60 × 8

Distance = 480 km

Therefore, distance to be covered is 480 km.

By the formula,

$\underline{\boxed{\sf Total \ speed=\dfrac{Total \ distance}{Total \ time} }}$

Given that,

Distance (d) = 480 km

Time (t) = 7.5 hours

Substituting their values,

Speed = 480/7.5

Speed = 64 km/hr

According to the question,

Increase in speed = Increased speed - Original Speed

By substituting,

Increase in speed = 64 - 60

Increase in speed = 4 km/hr

Therefore, the increase in speed is 4 km/hr.