Question

John walks for 10min with a speed of 9km/h. With what speed should he walk to cover 20mins with an average speed of 12km/h

Answer 1

Step-by-step explanation:

☛Question:-

John walks for 10min with a speed of 9km/h. With what speed should he walk to cover 20mins with an average speed of 12km/h.

☞Answer:-

Given:-

• Jhon's walking speed is 9km/h (10 min)

To find:-

• The avarage speed of 20 min walk.

Solution:-

⇝ Average speed = Total Distance / Total time

Total time = 30 min = 1/2 hr

Average speed = 12 kmph

Total Distance = Average speed × Total time = 12 × 1/2 km = 6 km

Let the speed for the last 20 min be x kmph

Total Distance = distance covered with speed 9 kmph and 12 kmph

= 9 × 1/6 + x × 1/3………. as Time(9 kmph) = 10 min Time(x kmph) = 20 min

6 = 3/2 + x/3

x/3 = 6-1.5

x/3 = 4.5

✪ x = 13.5 kmph

The speed for last 20 min is 13.5 kmph.

✯Note:

Conversion used

⇢ 1 hr = 60 min

☘ᕼᗴᑎᑕᗴ,

Tᕼᗴ ᗩᑎՏᗯᗴᖇ IՏ 13.5 Kᗰ/ᕼ.