The average speed of a train is 180% of the average speed of a car. The car covers a distance of 990 km in 15 hours. The time taken (in hours) by the train to cover the distance of 891 km is:
- A9
2
1
- B7
2
1
- C6
2
1
- D5
2
1
Solution & Step-by-step Explanation
Step 1: Find the speed of the car.
Speed of car=
Time
Distance
=
15
990
=66 km/h
Step 2: Find the speed of the train.
Speed of train=180% of 66=
100
180
×66=1.8×66=118.8 km/h
Step 3: Calculate the time taken by the train to cover 891 km.
Time=
Speed
Distance
=
118.8
891
=
1188
8910
Dividing both the numerator and denominator by 99:
8910÷99=90
1188÷99=12
Time=
12
90
=
2
15
=7
2
1
hours
Speed of car=
Time
Distance
=
15
990
=66 km/h
Step 2: Find the speed of the train.
Speed of train=180% of 66=
100
180
×66=1.8×66=118.8 km/h
Step 3: Calculate the time taken by the train to cover 891 km.
Time=
Speed
Distance
=
118.8
891
=
1188
8910
Dividing both the numerator and denominator by 99:
8910÷99=90
1188÷99=12
Time=
12
90
=
2
15
=7
2
1
hours