Objective
Marks
+1
Question No. 19
A car takes 24 hours to reach a destination by travelling at the speed of 60 km/h. How
long will it take when the car travels at the speed of 80 km/h?
(a)15 hours
(b) 18 hours (c) 20 hours
(d)21 hours
Answers
gaxataisg nzkpz dwoakw
Answer:
b) 18 hours.
Step-by-step explanation:
♡ Speed of the car = 60km/h.
☆Let the distance travelled by the car be = D¹.
☆Let the time taken by the car to reach its destination be = T¹.
☆Let the speed of the car be = S¹.
¤ Distance travelled by the car = D¹
¤ Time taken by the car to reach its destination = 24h.
¤ Speed of the car = 60km/h.
● Speed of the car.
S¹ = D¹/T¹.
60km/h = D¹/24h.
60 × 24 = D¹.
1440km = D¹.
D¹ = 1440km.
distance travelled by the car is 1440km.
♡ When the speed of the car is 80km/h.
☆ Distance travelled by the car will remained same = 1440km.
☆ Let the time taken by the car to cover the distance of 1440km be = T².
☆ Let the speed of the car be = S².
¤ Distance(D¹) travelled by the car will remained the same = 1440km.
¤ Time taken by the car to reach its destination when its speed is 80km/h = T².
¤ speed of the car = 80km/h.
● Speed of the car.
S² = D¹/T².
80km/h = 1440km/T².
80T² = 1440km.
T² = 1440/80.
T² = 18h.
Hence, the car will take 18 hours to to cover the distance of 1440km with the speed of 80km/h.