A car covers a distance in 40 minutes with an average speed of 60 km per hour. The average speed to cover the same distance in 30 minutes is
(a) 80 km/h
(b) 45/2 km/h
(c) 70 km/h
(d) 45 km/h
Solution:
Average speed of the car = 60 Km/hour
Distance covered in 40 minutes = 60 × (40/60) Km = 60 × (2/3) = 40 km
Speed required to cover 40 km in 30 minutes = 40/(30/60) = (40 × 60)/30 Km/h = 80Km/hour
The answer is (a)
✦ Try This: A car covers a distance in 30 minutes with an average speed of 56 km per hour. The average speed to cover the same distance in 24 minutes is (a) 80 km/h, (b) 45/2 km/h, (c) 70 km/h, (d) 45 km/h
Average speed of the car = 56 Km/hour
Distance covered in 30 minutes = 56 × (30/60) Km = 56× (1/2) = 28 km
Speed required to cover 40 km in 30 minutes = 28/(15/60) = (28 × 60)/24 Km/h = 70Km/hour
Answer is (c).
☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 13
NCERT Exemplar Class 8 Maths Chapter 10 Sample Problem 2
A car covers a distance in 40 minutes with an average speed of 60 km per hour. The average speed to cover the same distance in 30 minutes is (a) 80 km/h, (b) 45/2 km/h, (c) 70 km/h, (d) 45 km/h
Summary:
A car covers a distance in 40 minutes with an average speed of 60 km per hour. The average speed to cover the same distance in 30 minutes is 80 Km /hour
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