Question

Every Monday Simi travels by car to the library.
The distance is 20km and the journey takes 23 minutes.
a) Calculate the average speed for the journey in kilometers per
hour.
b) On Monday, she is delayed and her average speed is reduced to 32km/h.
Calculate the percentage increase in journey time.​

Answer 1

Answer:

8% easy answer 45 km driving

Answer 2

Given,

Distance of the journey = 20 km

Time taken = 23 minutes

To find,

1. Average speed of the journey. (in km/h)
2. If she is delayed and her average speed is reduced to 32km/h, then the amount percentage increase in journey time.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

Now,

1 hour = 60 minutes

So,

Simi travels in 23 minutes = 20 km

Simi travels in 1 minute = 20/23 km

Simi travels in 60 minutes = (20×60)/23 km

Or, Simi travels in 1 hour = 1200/23 = 52.17 km (approx.)

Thus,

Her average speed is = 52.17 km/h

Now,

Her average speed is reduced to 32 km/h

So,

She travels 32 km in = 1 hour

Or, she travels 32 km in = 60 minutes

She travels 1 km in = 60/32 minutes

She travels 20 km in = (60×20)/32 = 37.5 minutes

So,

Journey time increased by = 37.5-23 = 14.5 minutes

Percentage of time increase = 100 × 14.5/23 = 63.04% (approx.)

Hence, her average speed was approximately 52.17 km/h and journey time had increased by approximately 63.04%