SA3 marksYear: 2020MediumCBSE Class 10
quadratic-equationsspeed-distance-timeword-problem
Question
In a flight of 600 km, an aircraft was slowed due to bad weather. Its average speed for the trip was reduced to 200 km/hr and time of flight increased by 30 minutes. Find the original duration of flight.
Solution
1
Let the speed of aircraft be x km/hr.
x−200600−x600=6030
+1 mark2
⇒x2−200x−240000=0
(x−600)(x+400)=0
+1 mark3
x=600 (rejecting x=−400).
Speed of aircraft =600 km/hr.
Duration of flight =600600=1 hr.
+1 mark