In a flight of 600 km an aircraft was slowed due to

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Question 5:  In a flight of 600 km an aircraft was slowed due to bad weather. Its average speed for the trip was reduced by 200km/hr and time of flight increased by 30 minutes. Find the original duration of flight.     [CBSE  2020]

Solution : Let the actual speed of flight = ‘x’  km/h

So, time taken by the flight at actual speed = \frac{600}{x} hr

Reduse speed of the flight = (x – 200) km/h

So, time taken by the flight at the Reduse speed =\frac{600}{(x - 200)} hr

According to the given condition

\Rightarrow \dfrac{600}{x - 200} - \dfrac{360}{x} = \frac{30}{60}

\Rightarrow \dfrac{600[x - (x - 200)]}{x(x - 200)} = \frac{1}{2}

\Rightarrow \dfrac{600\times 200}{x(x - 200)} = \frac{1}{2}

⇒  120000×2 = x(x – 200)

⇒  x² – 200 x – 240000 = 0

⇒  x² – 600 x + 400 x – 240000 = 0

⇒  x(x – 600) + 400(x – 600) =0

⇒  (x – 600 )(x + 400) = 0

⇒   x = 600,  – 400(Speed of flight can not be negative)

Hence, speed of flight = 600 km/h


 Question:1

If Ritu were younger by 5 years than what she really is, then the square of her age would have been 11 more than five times her present age. What is her present age ?                   [CBSE Term-2 SQP 2022]

Solution: For solution please  click here

Question 2:

The sum of areas of two squares is 157 m². If the sum of their perimeters is 68 m, find the sides of the two squares.                     [CBSE 2019]

Solution:  For solution please  click here

Question 3:

If the equation (1 + m²)x² + 2 mcx + c² – a² = 0 has equal roots then show that c² = a²(1 + m²).

[CBSE 2017]

Solution: For solution please click here



Question 4:

A train covers a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, it would have taken 3 hours more to cover the same distance. Find the original speed of the train.                [CBSE    2020]

Solution:For solution please  click here

Question 6:

A train travels 360 km at a uniform speed. If the speed had been 5 km/hr more, it would have taken 1 hours less for the same journey. Find the speed of the train.                                                                                   [CBSE  2019]

Solution: For solution please click here

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