Here we will learn to solve different types of problems on calculating distance.
We know, the formula to find out distance = speed × time
Word problems on calculating distance:
1. A train moves at a speed of 80 km/hr. How far will it travel in 36 minutes?
Using the unitary method;
In 60 minutes, distance covered = 80 km
In 1 minute, distance covered = 80/60 km
Speed = 80 km/hr
Time = 36 minutes or 36/60 hours
We know, formula of distance = speed × time
= 80 × 36/60
= 48 km
Therefore, the train will travel 48 km in 36 minutes.
2. A student goes to school at the rate of 7 ½ km/hr and reaches 10 minutes late. If he travels at the speed of 10 km/hr he is 10 minutes early. What is the distance to the school?
Let the distance to school be 1 km, then time taken to cover 1 km at the rate of 7 1/2 km/hr
= Distance /speed = 1/(15/2) = 2/15 hr = 2/15 × 60 minutes = 8 minutes
Time taken to cover 1 km at the rate of 10 km/hr
= Distance /speed = 1/10 hr = 1/10 × 60 minutes = 6 minutes
Therefore, difference in time taken = (8 – 6) minutes = 2 minutes
But actual difference in time is 20 minutes
When the difference in time is 2 minutes, distance to school = 1 km
When the difference in time is 1 minute, distance to school = 1/2 km
When the difference in time is 20 minutes, distance to school = 1/2 × 20 km
Therefore, the distance to school is 10 km.
3. Two persons jog and covers the same distance at the speed of 6 km/hr and 4 km/hr. Find the distance covered by each one of them when one takes 10 minutes longer than the other.
Let the required distance be x km
Time taken to cover x km at 6 km/hr = x/6 hr
Time taken to cover x km at 4 km/hr = x/4 hr
According to the question, x/4 – x/6 = 10/60
⇒ x/4 – x/6 = 1/6
⇒ 3x – 2x /12 = 1/6
⇒ x/12 = 1/6
⇒ x = 12/6
Therefore, the required distance is 2 km.
Relationship between Speed, Distance and Time
Problems on Calculating Distance
Two Objects Move in Same Direction
Two Objects Move in Opposite Direction
Train Passes a Moving Object in the Same Direction
Train Passes a Moving Object in the Opposite Direction
Two Trains Passes in the Same Direction
Two Trains Passes in the Opposite Direction
8th Grade Math Practice
From Problems on Calculating Distance to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.
New! CommentsHave your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.