Question

A car move with a speed of 40 km/h for 15 minutes and then with a speed of a 60km /h
the next 15 minutes. The total distance covered by the car is:
1) 25km
100 km
i) 15km
Those who will answer I will him or her a brainalist​

Answer 1

Given :-

▪ A car moved with a speed of 40 km/hr for 15 minutes and then with a speed of 60 km/hr for the next 15 minutes.

To Find :-

▪ Total distance travelled by the body.

Solution :-

We are given speed and time in different units, so first, we have to make them of same units like if the time is given in minutes then the speed should in distance travelled per minute.

Let us convert the speed from km/hr to km/min

We know, 1 hour = 60 minutes , so

⇒ 40 km/hr

⇒ 40/60 × km/min

⇒ 4/6 km/min

⇒ 2/3 km/min

Also,

⇒ 60 km/hr

⇒ 60/60 km/min

⇒ 1 km/min

Now, There are two situations,

[1]

The car moved with a speed of 2/3 km/min for 15 minutes, so we have

• Speed = 2/3 km/min
• Time = 15 minutes

Hence, Distance travelled in this journey can be calculated as

⇒ Distance = Speed × Time

⇒ d₁ = 2/3 × 15

⇒ d₁ = 2 × 5

⇒ d₁ = 10 km

[2]

The body moved with a speed of 1 km/min for again, 15 minutes. so we have

• Speed = 1 km/min
• Time = 15 minutes

Similarly, the distance travelled in this journey can be calculated as

⇒ Distance = Speed × Time

⇒ d₂ = 1 × 15

⇒ d₂ = 15 km

Now, The total distance travelled by the car is the sum of Distances covered in both the situations, which is

⇒ Total distance travelled = d₁ + d₂

⇒ Total distance travelled = 10 + 15

⇒ Total distance travelled = 25 km

∴ Option (1) is correct.