if the speed of a car is increased by 20 km per hr, it takes 24 minutes less to cover a distance of 48 km. find the speed of the car.
Answers
Step-by-step explanation:
Let the speed of the car be s and time be t
Then, st=240⟹s=
t
240
and (s+20)(t−2)=240
(
t
240
+20)(t−2)=240
(20t+240)(t−2)=240t
20t
2
+240t−480−40t=240t
20t
2
−40t−480=0
t
2
−2t−24=0
(t−6)(t+4)=0
t=−4,6
Hence, time is 6 hr
and speed =
6
240
=40km/hr
Answer:
Yes! Here is your answer!
Step-by-step explanation:
Formula: Speed = Distance/ Time, Therefore, Time = Distance / speed
Given that speed of the car is 20km/hr more than the average speed of the bus, Let the speed of the bus be x,
Therefore speed of the car is x+20.
Average speed of the bus:
300/x - 4=300/x+20
=> 300[x+20-x/x(x+20)]= 4
=> 300(20/ x(x+20)) = 4
=> 300(20/x²+20x) = 4 (upon cross multiplying)
=> 6000= 4x²+80x
4x²+80x-6000=0
4(x² + 20x -1500) =0
x²+20x-1500=0
Upon factorizing,
(x+50)(x-30)=0
x=30
The bus goes 30 kmph; the car goes 50 kmph