2x + 3y = 12; x - y = 1 Solve the following sub - questions. (Any Two): 1) A car covers a distance of 240 km with some speed. If the speed is increased by 20 km/h, it will cover the same distance in 2 hours less. Find the speed of the car.
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Answer:
Correct option is A)
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
2
−6t+4t−24=0
(t−6)(t+4)=0
t=−4,6
Hence, time is 6 hr
and speed =
6
240
=40km/hr
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