Question

A car moves with a speed of 80 kmph for 15 minutes and then with a speed of 60 kmph for next 15

minutes. The total distance covered by the car is [ ]


a) 100 km
b) 50 km
c) 35 km
d) 70 km​

Answer 1

$\frac{80}{4} = 20 \\ \frac{60}{4} = 15 \\ so \: 20 + 15 = 35 \: km \: is \: covered \: by \: the \: car$

Answer 2

Given:

• The car moves with a speed 80 of km/h for 15 minutes.
• Then the car moves with a speed of 16 km/h for next 15 minutes.

To find:

The total distance covered by the car in the total duration of time.

Solution:

Case - 1:

Speed = 80 km/h

Time = 15 minutes.

Hence,

In 60 minutes the car covers a distance of 80 km .[∵ 1 hour = 60 minutes.]

∴ In 1 minute the car covers a distance of (80/60) km

∴ In 15 minutes the car covers a distance of_

(80×15/60)

=(80/4)

= 20 km.

∴ In first 15 minutes the car covers a distance of 20 km.

Case-2:

Speed = 60 km/h

Time = 15 minutes.

Hence,

In 60 minutes the car covers a distance of 60 km .[∵ 1 hour = 60 minutes.]

∴ In 1 minute the car covers a distance of (60/60) km

∴ In 15 minutes the car covers a distance of_

(60×15/60)

= 15 km.

∴ In next 15 minutes the car covers a distance of 15 km.

∴ Total distance covered by the car in the total duration of time _

(20+15) km

= 35 km.

Answer:

Total distance covered by the car is 35 km.

So the answer is option ,

c) 70 km.