Exercise 12 (B) Question 4 - Selina Mathematic Class 6 – Idea of Speed, ...

Problem 4 B (i) Mr. Amit can walk 8 km in 1 hour 20 minutes, How long will it take him to walk 6.5 km?, Selina concise maths solution, Problem 4 B (i): Mr. Amit can walk 8 km in 1 hour 20 minutes, How long will it take him to walk 6.5 km?,

Problem 4 B (i) Mr. Amit can walk 8 km in 1 hour 20 minutes, How long will it take him to walk 6.5 km?, Selina concise maths solution, Problem 4 B (i): Mr. Amit can walk 8 km in 1 hour 20 minutes, How long will it take him to walk 6.5 km?,

Mr. Amit can walk 8 km in 1 hour 20 minutes. How far does he go in 30 seconds?

Given

8 km is covered in 1 hour 20 minutes

So,

Distance =8 km

Time=1hour20minutes

=1+20/60

=1+1/3

We get,

=4/3 hours

Hence,

Speed =8km/4/3hours

=(8×3)/4km/h

We get,

= 6 km/h

Now, the distance covered in 30 seconds is as follows

Speed =6km/h

Time =30sec

Hence,

Distance =6×[30/(60×60)]km

On further calculation, we get

=1/(10×2)km

=1/20×1000m

=1/2×100

=50m

Therefore, the distance covered by Mr. Amit in 30 seconds is 50 m

 

Mr. Amit can walk 8 km in 1 hour 20 minutes. How far does he go in 10 minutes?

Given

8 km is covered in 1 hour 20 minutes

Distance =8 km

Time =1hours20minutes

=1+20/60

=1+1/3

We get,

=4/3 hours

Hence,

Speed=8km/(4/3)hours

Speed=(8×3)/4km/h

Speed=2×3km/h

Speed=6km/h

Now, distance covered in 10 minutes is as follows

Speed=6km/h

Time=10min

=10/60hour

=1/6hour

Hence,

Distance =6×1/6

We get,

=1 km

Therefore, the distance covered by Mr. Amit in 10 min is 1 km